Answer:
def stable_merge(left, right, key):
 i = j = 0
 out = []
 while i < len(left) and j < len(right):
 if key(right[j]) < key(left[i]):
 out.append(right[j])
 j += 1
 else:
 out.append(left[i])
 i += 1
 out.extend(left[i:])
 out.extend(right[j:])
 return out

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def stable_merge(left, right, key):
    i = j = 0
    out = []
    while i < len(left) and j < len(right):
        if key(right[j]) < key(left[i]):
            out.append(right[j])
            j += 1
        else:
            out.append(left[i])
            i += 1
    out.extend(left[i:])
    out.extend(right[j:])
    return out

import unittest
from solution import stable_merge

class Test(unittest.TestCase):
    def test_stable(self):
        left = [("a", 1), ("c", 1)]
        right = [("b", 1)]
        merged = stable_merge(left, right, lambda p: p[1])
        self.assertEqual([p[0] for p in merged], ["a", "c", "b"])
    def test_order(self):
        self.assertEqual(stable_merge([1, 4], [2, 3], lambda x: x), [1, 2, 3, 4])

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `stable_merge(left, right, key) -> list`.

Merge two lists already sorted by `key` into one sorted list. Equal keys must
keep all items from `left` before items from `right` (stable).


Answer:
def stable_merge(left, right, key):
 i = j = 0
 out = []
 while i < len(left) and j < len(right):
 if key(right[j]) < key(left[i]):
 out.append(right[j])
 j += 1
 else:
 out.append(left[i])
 i += 1
 out.extend(left[i:])
 out.extend(right[j:])
 return out

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 2, "errors": 0, "skipped": 0, "passed": false}

test_order (test_solution.Test.test_order) ... FAIL
test_stable (test_solution.Test.test_stable) ... FAIL

======================================================================
FAIL: test_order (test_solution.Test.test_order)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-fva3gt55\test_solution.py", line 11, in test_order
    self.assertEqual(stable_merge([1, 4], [2, 3], lambda x: x), [1, 2, 3, 4])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [2, 3, 1, 4] != [1, 2, 3, 4]

First differing element 0:
2
1

- [2, 3, 1, 4]
?        ---

+ [1, 2, 3, 4]
?  +++

======================================================================
FAIL: test_stable (test_solution.Test.test_stable)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-fva3gt55\test_solution.py", line 9, in test_stable
    self.assertEqual([p[0] for p in merged], ["a", "c", "b"])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: ['b', 'a', 'c'] != ['a', 'c', 'b']

First differing element 0:
'b'
'a'

- ['b', 'a', 'c']
+ ['a', 'c', 'b']

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=2)

Takes from right on ties, breaking stability.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `stable_merge(left, right, key) -> list`.

Merge two lists already sorted by `key` into one sorted list. Equal keys must
keep all items from `left` before items from `right` (stable).

--- solution.py (buggy) ---
def stable_merge(left, right, key):
 i = j = 0
 out = []
 while i < len(left) and j < len(right):
 if key(left[i]) <= key(right[j]):
 out.append(right[j])
 j += 1
 else:
 out.append(left[i])
 i += 1
 out.extend(left[i:])
 out.extend(right[j:])
 return out

--- test_solution.py ---
import unittest
from solution import stable_merge

class Test(unittest.TestCase):
 def test_stable(self):
 left = [("a", 1), ("c", 1)]
 right = [("b", 1)]
 merged = stable_merge(left, right, lambda p: p[1])
 self.assertEqual([p[0] for p in merged], ["a", "c", "b"])
 def test_order(self):
 self.assertEqual(stable_merge([1, 4], [2, 3], lambda x: x), [1, 2, 3, 4])

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 2, "errors": 0, "skipped": 0, "passed": false}

test_order (test_solution.Test.test_order) ... FAIL
test_stable (test_solution.Test.test_stable) ... FAIL

======================================================================
FAIL: test_order (test_solution.Test.test_order)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-fva3gt55\test_solution.py", line 11, in test_order
 self.assertEqual(stable_merge([1, 4], [2, 3], lambda x: x), [1, 2, 3, 4])
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [2, 3, 1, 4] != [1, 2, 3, 4]

First differing element 0:
2
1

- [2, 3, 1, 4]
? ---

+ [1, 2, 3, 4]
? +++

======================================================================
FAIL: test_stable (test_solution.Test.test_stable)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-fva3gt55\test_solution.py", line 9, in test_stable
 self.assertEqual([p[0] for p in merged], ["a", "c", "b"])
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: ['b', 'a', 'c'] != ['a', 'c', 'b']

First differing element 0:
'b'
'a'

- ['b', 'a', 'c']
+ ['a', 'c', 'b']

-----------------------------------------------------

OPEN_REASON_RESULT {"tests_run": 2, "failures": 0, "errors": 0, "skipped": 0, "passed": true}


Answer:
def insert(root, value):
 if root is None:
 return {"v": value, "l": None, "r": None}
 if value < root["v"]:
 root["l"] = insert(root["l"], value)
 elif value > root["v"]:
 root["r"] = insert(root["r"], value)
 return root

def contains(root, value):
 cur = root
 while cur is not None:
 if value == cur["v"]:
 return True
 cur = cur["l"] if value < cur["v"] else cur["r"]
 return False

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def insert(root, value):
    if root is None:
        return {"v": value, "l": None, "r": None}
    if value < root["v"]:
        root["l"] = insert(root["l"], value)
    elif value > root["v"]:
        root["r"] = insert(root["r"], value)
    return root

def contains(root, value):
    cur = root
    while cur is not None:
        if value == cur["v"]:
            return True
        cur = cur["l"] if value < cur["v"] else cur["r"]
    return False

import unittest
from solution import insert, contains

class Test(unittest.TestCase):
    def test_roundtrip(self):
        root = None
        for x in [5, 3, 7, 3]:
            root = insert(root, x)
        self.assertTrue(contains(root, 3))
        self.assertTrue(contains(root, 7))
        self.assertFalse(contains(root, 4))
    def test_empty(self):
        self.assertFalse(contains(None, 1))

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement a tiny BST: `insert(root, value)` returning the new root, and
`contains(root, value) -> bool`. Nodes are dicts `{"v": int, "l": node|None, "r": node|None}`.
Duplicate inserts are no-ops. `root` may be None.


Answer:
def insert(root, value):
 if root is None:
 return {"v": value, "l": None, "r": None}
 if value < root["v"]:
 root["l"] = insert(root["l"], value)
 elif value > root["v"]:
 root["r"] = insert(root["r"], value)
 return root

def contains(root, value):
 cur = root
 while cur is not None:
 if value == cur["v"]:
 return True
 cur = cur["l"] if value < cur["v"] else cur["r"]
 return False

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_empty (test_solution.Test.test_empty) ... ok
test_roundtrip (test_solution.Test.test_roundtrip) ... FAIL

======================================================================
FAIL: test_roundtrip (test_solution.Test.test_roundtrip)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-c5vkjy71\test_solution.py", line 9, in test_roundtrip
    self.assertTrue(contains(root, 3))
    ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
AssertionError: False is not true

----------------------------------------------------------------------
Ran 2 tests in 0.000s

FAILED (failures=1)

Always inserts on the right and only checks the root.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement a tiny BST: `insert(root, value)` returning the new root, and
`contains(root, value) -> bool`. Nodes are dicts `{"v": int, "l": node|None, "r": node|None}`.
Duplicate inserts are no-ops. `root` may be None.

--- solution.py (buggy) ---
def insert(root, value):
 if root is None:
 return {"v": value, "l": None, "r": None}
 root["r"] = insert(root["r"], value)
 return root

def contains(root, value):
 return root is not None and root["v"] == value

--- test_solution.py ---
import unittest
from solution import insert, contains

class Test(unittest.TestCase):
 def test_roundtrip(self):
 root = None
 for x in [5, 3, 7, 3]:
 root = insert(root, x)
 self.assertTrue(contains(root, 3))
 self.assertTrue(contains(root, 7))
 self.assertFalse(contains(root, 4))
 def test_empty(self):
 self.assertFalse(contains(None, 1))

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_empty (test_solution.Test.test_empty) ... ok
test_roundtrip (test_solution.Test.test_roundtrip) ... FAIL

======================================================================
FAIL: test_roundtrip (test_solution.Test.test_roundtrip)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-c5vkjy71\test_solution.py", line 9, in test_roundtrip
 self.assertTrue(contains(root, 3))
 ~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
AssertionError: False is not true

----------------------------------------------------------------------
Ran 2 tests in 0.000s

FAILED (failures=1)


Answer:
from collections import OrderedDict

class LRUCache:
 def __init__(self, capacity):
 self.cap = capacity
 self.data = OrderedDict()

 def get(self, key):
 if key not in self.data:
 return None
 self.data.move_to_end(key)
 return self.data[key]

 def put(self, key, value):
 if key in self.data:
 self.data.move_to_end(key)
 self.data[key] = value
 if len(self.data) > self.cap:
 self.data.popitem(last=False)

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

from collections import OrderedDict

class LRUCache:
    def __init__(self, capacity):
        self.cap = capacity
        self.data = OrderedDict()

    def get(self, key):
        if key not in self.data:
            return None
        self.data.move_to_end(key)
        return self.data[key]

    def put(self, key, value):
        if key in self.data:
            self.data.move_to_end(key)
        self.data[key] = value
        if len(self.data) > self.cap:
            self.data.popitem(last=False)

import unittest
from solution import LRUCache

class Test(unittest.TestCase):
    def test_evict(self):
        c = LRUCache(2)
        c.put("a", 1)
        c.put("b", 2)
        c.get("a")
        c.put("c", 3)
        self.assertIsNone(c.get("b"))
        self.assertEqual(c.get("a"), 1)
        self.assertEqual(c.get("c"), 3)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement class `LRUCache(capacity)` with `get(key)` and `put(key, value)`.

Capacity is a positive int. `get` returns the value or None. `put` inserts or
updates; if the cache exceeds capacity, evict the least recently used key.
Both get and put count as use.

OPEN_REASON_RESULT {"tests_run": 1, "failures": 0, "errors": 0, "skipped": 0, "passed": true}


Answer:
from collections import OrderedDict

class LRUCache:
 def __init__(self, capacity):
 self.cap = capacity
 self.data = OrderedDict()

 def get(self, key):
 if key not in self.data:
 return None
 self.data.move_to_end(key)
 return self.data[key]

 def put(self, key, value):
 if key in self.data:
 self.data.move_to_end(key)
 self.data[key] = value
 if len(self.data) > self.cap:
 self.data.popitem(last=False)

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 1, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_evict (test_solution.Test.test_evict) ... FAIL

======================================================================
FAIL: test_evict (test_solution.Test.test_evict)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-_6g9qfki\test_solution.py", line 11, in test_evict
    self.assertIsNone(c.get("b"))
    ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
AssertionError: 2 is not None

----------------------------------------------------------------------
Ran 1 test in 0.000s

FAILED (failures=1)

get does not refresh recency; evicts most recently inserted.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement class `LRUCache(capacity)` with `get(key)` and `put(key, value)`.

Capacity is a positive int. `get` returns the value or None. `put` inserts or
updates; if the cache exceeds capacity, evict the least recently used key.
Both get and put count as use.

--- solution.py (buggy) ---
from collections import OrderedDict

class LRUCache:
 def __init__(self, capacity):
 self.cap = capacity
 self.data = OrderedDict()

 def get(self, key):
 return self.data.get(key)

 def put(self, key, value):
 self.data[key] = value
 if len(self.data) > self.cap:
 self.data.popitem(last=True)

--- test_solution.py ---
import unittest
from solution import LRUCache

class Test(unittest.TestCase):
 def test_evict(self):
 c = LRUCache(2)
 c.put("a", 1)
 c.put("b", 2)
 c.get("a")
 c.put("c", 3)
 self.assertIsNone(c.get("b"))
 self.assertEqual(c.get("a"), 1)
 self.assertEqual(c.get("c"), 3)

--- failure ---
OPEN_REASON_RESULT {"tests_run": 1, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_evict (test_solution.Test.test_evict) ... FAIL

======================================================================
FAIL: test_evict (test_solution.Test.test_evict)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-_6g9qfki\test_solution.py", line 11, in test_evict
 self.assertIsNone(c.get("b"))
 ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
AssertionError: 2 is not None

----------------------------------------------------------------------
Ran 1 test in 0.000s

FAILED (failures=1)


Answer:
def inversions(xs):
 n = len(xs)
 count = 0
 for i in range(n):
 for j in range(i + 1, n):
 if xs[i] > xs[j]:
 count += 1
 return count

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def inversions(xs):
    n = len(xs)
    count = 0
    for i in range(n):
        for j in range(i + 1, n):
            if xs[i] > xs[j]:
                count += 1
    return count

import unittest
from solution import inversions

class Test(unittest.TestCase):
    def test_rev(self):
        self.assertEqual(inversions([3, 2, 1]), 3)
    def test_sorted(self):
        self.assertEqual(inversions([1, 2, 3]), 0)
    def test_empty(self):
        self.assertEqual(inversions([]), 0)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `inversions(xs: list[int]) -> int`.

Return the number of pairs i < j with xs[i] > xs[j]. Empty or sorted lists are 0.
n will be small enough for O(n^2).

test_empty (test_solution.Test.test_empty) ... ok
test_rev (test_solution.Test.test_rev) ... ok
test_sorted (test_solution.Test.test_sorted) ... ok

----------------------------------------------------------------------
Ran 3 tests in 0.000s

OK

OPEN_REASON_RESULT {"tests_run": 3, "failures": 0, "errors": 0, "skipped": 0, "passed": true}


Answer:
def inversions(xs):
 n = len(xs)
 count = 0
 for i in range(n):
 for j in range(i + 1, n):
 if xs[i] > xs[j]:
 count += 1
 return count

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 3, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_empty (test_solution.Test.test_empty) ... ok
test_rev (test_solution.Test.test_rev) ... FAIL
test_sorted (test_solution.Test.test_sorted) ... ok

======================================================================
FAIL: test_rev (test_solution.Test.test_rev)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-ms6zex3x\test_solution.py", line 6, in test_rev
    self.assertEqual(inversions([3, 2, 1]), 3)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 2 != 3

----------------------------------------------------------------------
Ran 3 tests in 0.000s

FAILED (failures=1)

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `inversions(xs: list[int]) -> int`.

Return the number of pairs i < j with xs[i] > xs[j]. Empty or sorted lists are 0.
n will be small enough for O(n^2).

--- solution.py (buggy) ---
def inversions(xs):
 return sum(1 for a, b in zip(xs, xs[1:]) if a > b)

--- test_solution.py ---
import unittest
from solution import inversions

class Test(unittest.TestCase):
 def test_rev(self):
 self.assertEqual(inversions([3, 2, 1]), 3)
 def test_sorted(self):
 self.assertEqual(inversions([1, 2, 3]), 0)
 def test_empty(self):
 self.assertEqual(inversions([]), 0)

--- failure ---
OPEN_REASON_RESULT {"tests_run": 3, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_empty (test_solution.Test.test_empty) ... ok
test_rev (test_solution.Test.test_rev) ... FAIL
test_sorted (test_solution.Test.test_sorted) ... ok

======================================================================
FAIL: test_rev (test_solution.Test.test_rev)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-ms6zex3x\test_solution.py", line 6, in test_rev
 self.assertEqual(inversions([3, 2, 1]), 3)
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 2 != 3

----------------------------------------------------------------------
Ran 3 tests in 0.000s

FAILED (failures=1)


Answer:
def one_edit(a, b):
 if a == b:
 return True
 if abs(len(a) - len(b)) > 1:
 return False
 if len(a) == len(b):
 return sum(x != y for x, y in zip(a, b)) == 1
 if len(a) > len(b):
 a, b = b, a
 i = j = 0
 skipped = False
 while i < len(a) and j < len(b):
 if a[i] == b[j]:
 i += 1
 j += 1
 continue
 if skipped:
 return False
 skipped = True
 j += 1
 return True

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def one_edit(a, b):
    if a == b:
        return True
    if abs(len(a) - len(b)) > 1:
        return False
    if len(a) == len(b):
        return sum(x != y for x, y in zip(a, b)) == 1
    if len(a) > len(b):
        a, b = b, a
    i = j = 0
    skipped = False
    while i < len(a) and j < len(b):
        if a[i] == b[j]:
            i += 1
            j += 1
            continue
        if skipped:
            return False
        skipped = True
        j += 1
    return True

import unittest
from solution import one_edit

class Test(unittest.TestCase):
    def test_sub(self):
        self.assertTrue(one_edit("cat", "cut"))
    def test_ins(self):
        self.assertTrue(one_edit("ca", "cat"))
    def test_two(self):
        self.assertFalse(one_edit("cat", "dog"))
    def test_same(self):
        self.assertTrue(one_edit("ab", "ab"))

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `one_edit(a: str, b: str) -> bool`.

True if a and b are equal, or differ by a single insert, delete, or substitute.
False otherwise.

test_ins (test_solution.Test.test_ins) ... ok
test_same (test_solution.Test.test_same) ... ok
test_sub (test_solution.Test.test_sub) ... ok
test_two (test_solution.Test.test_two) ... ok

----------------------------------------------------------------------
Ran 4 tests in 0.000s

OK

OPEN_REASON_RESULT {"tests_run": 4, "failures": 0, "errors": 0, "skipped": 0, "passed": true}


Answer:
def one_edit(a, b):
 if a == b:
 return True
 if abs(len(a) - len(b)) > 1:
 return False
 if len(a) == len(b):
 return sum(x != y for x, y in zip(a, b)) == 1
 if len(a) > len(b):
 a, b = b, a
 i = j = 0
 skipped = False
 while i < len(a) and j < len(b):
 if a[i] == b[j]:
 i += 1
 j += 1
 continue
 if skipped:
 return False
 skipped = True
 j += 1
 return True

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 4, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_ins (test_solution.Test.test_ins) ... ok
test_same (test_solution.Test.test_same) ... ok
test_sub (test_solution.Test.test_sub) ... ok
test_two (test_solution.Test.test_two) ... FAIL

======================================================================
FAIL: test_two (test_solution.Test.test_two)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-zhj4c5_4\test_solution.py", line 10, in test_two
    self.assertFalse(one_edit("cat", "dog"))
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: True is not false

----------------------------------------------------------------------
Ran 4 tests in 0.000s

FAILED (failures=1)

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `one_edit(a: str, b: str) -> bool`.

True if a and b are equal, or differ by a single insert, delete, or substitute.
False otherwise.

--- solution.py (buggy) ---
def one_edit(a, b):
 return abs(len(a) - len(b)) <= 1

--- test_solution.py ---
import unittest
from solution import one_edit

class Test(unittest.TestCase):
 def test_sub(self):
 self.assertTrue(one_edit("cat", "cut"))
 def test_ins(self):
 self.assertTrue(one_edit("ca", "cat"))
 def test_two(self):
 self.assertFalse(one_edit("cat", "dog"))
 def test_same(self):
 self.assertTrue(one_edit("ab", "ab"))

--- failure ---
OPEN_REASON_RESULT {"tests_run": 4, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_ins (test_solution.Test.test_ins) ... ok
test_same (test_solution.Test.test_same) ... ok
test_sub (test_solution.Test.test_sub) ... ok
test_two (test_solution.Test.test_two) ... FAIL

======================================================================
FAIL: test_two (test_solution.Test.test_two)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-zhj4c5_4\test_solution.py", line 10, in test_two
 self.assertFalse(one_edit("cat", "dog"))
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: True is not false

----------------------------------------------------------------------
Ran 4 tests in 0.000s

FAILED (failures=1)


Answer:
def has_cycle(head):
 slow = fast = head
 while fast is not None and fast["n"] is not None:
 slow = slow["n"]
 fast = fast["n"]["n"]
 if slow is fast:
 return True
 return False

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def has_cycle(head):
    slow = fast = head
    while fast is not None and fast["n"] is not None:
        slow = slow["n"]
        fast = fast["n"]["n"]
        if slow is fast:
            return True
    return False

import unittest
from solution import has_cycle

class Test(unittest.TestCase):
    def test_cycle(self):
        a = {"v": 1, "n": None}
        b = {"v": 2, "n": None}
        c = {"v": 3, "n": None}
        a["n"] = b
        b["n"] = c
        c["n"] = b
        self.assertTrue(has_cycle(a))
    def test_none(self):
        self.assertFalse(has_cycle(None))
    def test_line(self):
        a = {"v": 1, "n": {"v": 2, "n": None}}
        self.assertFalse(has_cycle(a))

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `has_cycle(head) -> bool`.

Linked list nodes are `{"v": any, "n": node|None}`. Detect a cycle using
constant extra memory (Floyd).

test_cycle (test_solution.Test.test_cycle) ... ok
test_line (test_solution.Test.test_line) ... ok
test_none (test_solution.Test.test_none) ... ok

----------------------------------------------------------------------
Ran 3 tests in 0.000s

OK


Answer:
def has_cycle(head):
 slow = fast = head
 while fast is not None and fast["n"] is not None:
 slow = slow["n"]
 fast = fast["n"]["n"]
 if slow is fast:
 return True
 return False

Do not weaken or delete tests
Keep the public API

Output: test_cycle (test_solution.Test.test_cycle) ...

Tracks values, not node identity, so duplicate values look like cycles.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `has_cycle(head) -> bool`.

Linked list nodes are `{"v": any, "n": node|None}`. Detect a cycle using
constant extra memory (Floyd).

--- solution.py (buggy) ---
def has_cycle(head):
 seen = []
 cur = head
 while cur is not None:
 if cur in seen:
 return True
 seen.append(cur["v"])
 cur = cur["n"]
 return False

--- test_solution.py ---
import unittest
from solution import has_cycle

class Test(unittest.TestCase):
 def test_cycle(self):
 a = {"v": 1, "n": None}
 b = {"v": 2, "n": None}
 c = {"v": 3, "n": None}
 a["n"] = b
 b["n"] = c
 c["n"] = b
 self.assertTrue(has_cycle(a))
 def test_none(self):
 self.assertFalse(has_cycle(None))
 def test_line(self):
 a = {"v": 1, "n": {"v": 2, "n": None}}
 self.assertFalse(has_cycle(a))

--- failure ---

test_cycle (test_solution.Test.test_cycle) ...


Answer:
from collections import defaultdict

def shortest_unique_prefix(words):
 trie = {}
 counts = defaultdict(int)
 for w in words:
 node = trie
 for ch in w:
 node = node.setdefault(ch, {})
 counts[id(node)] += 1
 node["$"] = True
 out = []
 for w in words:
 node = trie
 pref = []
 for ch in w:
 node = node[ch]
 pref.append(ch)
 if counts[id(node)] == 1:
 break
 out.append("".join(pref))
 return out

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

from collections import defaultdict

def shortest_unique_prefix(words):
    trie = {}
    counts = defaultdict(int)
    for w in words:
        node = trie
        for ch in w:
            node = node.setdefault(ch, {})
            counts[id(node)] += 1
        node["$"] = True
    out = []
    for w in words:
        node = trie
        pref = []
        for ch in w:
            node = node[ch]
            pref.append(ch)
            if counts[id(node)] == 1:
                break
        out.append("".join(pref))
    return out

import unittest
from solution import shortest_unique_prefix

class Test(unittest.TestCase):
    def test_basic(self):
        self.assertEqual(
            shortest_unique_prefix(["cat", "car", "dog"]),
            ["cat", "car", "d"],
        )
    def test_prefix_word(self):
        self.assertEqual(shortest_unique_prefix(["a", "ab"]), ["a", "ab"])

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `shortest_unique_prefix(words: list[str]) -> list[str]`.

For each word, return the shortest prefix that uniquely identifies it among
`words`. If a word is a prefix of another, the unique prefix is the whole word.
Assume words are distinct and nonempty.


Answer:
from collections import defaultdict

def shortest_unique_prefix(words):
 trie = {}
 counts = defaultdict(int)
 for w in words:
 node = trie
 for ch in w:
 node = node.setdefault(ch, {})
 counts[id(node)] += 1
 node["$"] = True
 out = []
 for w in words:
 node = trie
 pref = []
 for ch in w:
 node = node[ch]
 pref.append(ch)
 if counts[id(node)] == 1:
 break
 out.append("".join(pref))
 return out

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 2, "errors": 0, "skipped": 0, "passed": false}

test_basic (test_solution.Test.test_basic) ... FAIL
test_prefix_word (test_solution.Test.test_prefix_word) ... FAIL

======================================================================
FAIL: test_basic (test_solution.Test.test_basic)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-cxlkoac3\test_solution.py", line 6, in test_basic
    self.assertEqual(
    ~~~~~~~~~~~~~~~~^
        shortest_unique_prefix(["cat", "car", "dog"]),
        ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        ["cat", "car", "d"],
        ^^^^^^^^^^^^^^^^^^^^
    )
    ^
AssertionError: Lists differ: ['c', 'c', 'd'] != ['cat', 'car', 'd']

First differing element 0:
'c'
'cat'

- ['c', 'c', 'd']
+ ['cat', 'car', 'd']
?    ++     ++

======================================================================
FAIL: test_prefix_word (test_solution.Test.test_prefix_word)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-cxlkoac3\test_solution.py", line 11, in test_prefix_word
    self.assertEqual(shortest_unique_prefix(["a", "ab"]), ["a", "ab"])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: ['a', 'a'] != ['a', 'ab']

First differing element 1:
'a'
'ab'

- ['a', 'a']
+ ['a', 'ab']
?         +

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=2)

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `shortest_unique_prefix(words: list[str]) -> list[str]`.

For each word, return the shortest prefix that uniquely identifies it among
`words`. If a word is a prefix of another, the unique prefix is the whole word.
Assume words are distinct and nonempty.

--- solution.py (buggy) ---
def shortest_unique_prefix(words):
 return [w[:1] for w in words]

--- test_solution.py ---
import unittest
from solution import shortest_unique_prefix

class Test(unittest.TestCase):
 def test_basic(self):
 self.assertEqual(
 shortest_unique_prefix(["cat", "car", "dog"]),
 ["cat", "car", "d"],
 )
 def test_prefix_word(self):
 self.assertEqual(shortest_unique_prefix(["a", "ab"]), ["a", "ab"])

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 2, "errors": 0, "skipped": 0, "passed": false}

test_basic (test_solution.Test.test_basic) ... FAIL
test_prefix_word (test_solution.Test.test_prefix_word) ... FAIL

======================================================================
FAIL: test_basic (test_solution.Test.test_basic)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-cxlkoac3\test_solution.py", line 6, in test_basic
 self.assertEqual(
 ~~~~~~~~~~~~~~~~^
 shortest_unique_prefix(["cat", "car", "dog"]),
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 ["cat", "car", "d"],
 ^^^^^^^^^^^^^^^^^^^^
 )
 ^
AssertionError: Lists differ: ['c', 'c', 'd'] != ['cat', 'car', 'd']

First differing element 0:
'c'
'cat'

- ['c', 'c', 'd']
+ ['cat', 'car', 'd']
? ++ ++

======================================================================
FAIL: test_prefix_word (test_solution.Test.test_prefix_word)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-cxlkoac3\test_solution.py", line 11, in test_prefix_word
 self.assertEqual(shortest_unique_prefix(["a", "ab"]), ["a", "ab"])
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: ['a', 'a'] != ['a', 'ab']

Firs


Answer:
def merge_intervals(spans):
 if not spans:
 return []
 items = sorted((s, e) for s, e in spans)
 out = [list(items[0])]
 for s, e in items[1:]:
 if s <= out[-1][1]:
 out[-1][1] = max(out[-1][1], e)
 else:
 out.append([s, e])
 return out

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def merge_intervals(spans):
    if not spans:
        return []
    items = sorted((s, e) for s, e in spans)
    out = [list(items[0])]
    for s, e in items[1:]:
        if s <= out[-1][1]:
            out[-1][1] = max(out[-1][1], e)
        else:
            out.append([s, e])
    return out

import unittest
from solution import merge_intervals

class Test(unittest.TestCase):
    def test_overlap(self):
        self.assertEqual(merge_intervals([[1, 3], [2, 6], [8, 10]]), [[1, 6], [8, 10]])
    def test_touch(self):
        self.assertEqual(merge_intervals([[1, 2], [2, 3]]), [[1, 3]])
    def test_empty(self):
        self.assertEqual(merge_intervals([]), [])

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `merge_intervals(spans) -> list`.

`spans` is a list of [start, end] integer pairs with start <= end (closed).
Return merged disjoint intervals sorted by start.

test_empty (test_solution.Test.test_empty) ... ok
test_overlap (test_solution.Test.test_overlap) ... ok
test_touch (test_solution.Test.test_touch) ... ok

----------------------------------------------------------------------
Ran 3 tests in 0.000s

OK


Answer:
def merge_intervals(spans):
 if not spans:
 return []
 items = sorted((s, e) for s, e in spans)
 out = [list(items[0])]
 for s, e in items[1:]:
 if s <= out[-1][1]:
 out[-1][1] = max(out[-1][1], e)
 else:
 out.append([s, e])
 return out

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 3, "failures": 2, "errors": 0, "skipped": 0, "passed": false}

test_empty (test_solution.Test.test_empty) ... ok
test_overlap (test_solution.Test.test_overlap) ... FAIL
test_touch (test_solution.Test.test_touch) ... FAIL

======================================================================
FAIL: test_overlap (test_solution.Test.test_overlap)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-z610o6sq\test_solution.py", line 6, in test_overlap
    self.assertEqual(merge_intervals([[1, 3], [2, 6], [8, 10]]), [[1, 6], [8, 10]])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [[1, 3], [2, 6], [8, 10]] != [[1, 6], [8, 10]]

First differing element 0:
[1, 3]
[1, 6]

First list contains 1 additional elements.
First extra element 2:
[8, 10]

- [[1, 3], [2, 6], [8, 10]]
?      --------

+ [[1, 6], [8, 10]]

======================================================================
FAIL: test_touch (test_solution.Test.test_touch)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-z610o6sq\test_solution.py", line 8, in test_touch
    self.assertEqual(merge_intervals([[1, 2], [2, 3]]), [[1, 3]])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [[1, 2], [2, 3]] != [[1, 3]]

First differing element 0:
[1, 2]
[1, 3]

First list contains 1 additional elements.
First extra element 1:
[2, 3]

- [[1, 2], [2, 3]]
+ [[1, 3]]

----------------------------------------------------------------------
Ran 3 tests in 0.001s

FAILED (failures=2)

Sorts but never merges overlapping ranges.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `merge_intervals(spans) -> list`.

`spans` is a list of [start, end] integer pairs with start <= end (closed).
Return merged disjoint intervals sorted by start.

--- solution.py (buggy) ---
def merge_intervals(spans):
 return sorted(spans)

--- test_solution.py ---
import unittest
from solution import merge_intervals

class Test(unittest.TestCase):
 def test_overlap(self):
 self.assertEqual(merge_intervals([[1, 3], [2, 6], [8, 10]]), [[1, 6], [8, 10]])
 def test_touch(self):
 self.assertEqual(merge_intervals([[1, 2], [2, 3]]), [[1, 3]])
 def test_empty(self):
 self.assertEqual(merge_intervals([]), [])

--- failure ---
OPEN_REASON_RESULT {"tests_run": 3, "failures": 2, "errors": 0, "skipped": 0, "passed": false}

test_empty (test_solution.Test.test_empty) ... ok
test_overlap (test_solution.Test.test_overlap) ... FAIL
test_touch (test_solution.Test.test_touch) ... FAIL

======================================================================
FAIL: test_overlap (test_solution.Test.test_overlap)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-z610o6sq\test_solution.py", line 6, in test_overlap
 self.assertEqual(merge_intervals([[1, 3], [2, 6], [8, 10]]), [[1, 6], [8, 10]])
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [[1, 3], [2, 6], [8, 10]] != [[1, 6], [8, 10]]

First differing element 0:
[1, 3]
[1, 6]

First list contains 1 additional elements.
First extra element 2:
[8, 10]

- [[1, 3], [2, 6], [8, 10]]
? --------

+ [[1, 6], [8, 10]]

======================================================================
FAIL: test_touch (test_solution.Test.test_touch)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-z610o6sq\test_solution.py", line 8, in test_touch
 self.assertEqual(merge_intervals([[1, 2], [2, 3]]), [[1, 3]])
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
As


Answer:
def flatten(obj, prefix=""):
 if not isinstance(obj, dict):
 return {prefix: obj} if prefix else {"": obj}
 out = {}
 for k, v in obj.items():
 key = f"{prefix}.{k}" if prefix else str(k)
 if isinstance(v, dict):
 out.update(flatten(v, key))
 else:
 out[key] = v
 return out

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def flatten(obj, prefix=""):
    if not isinstance(obj, dict):
        return {prefix: obj} if prefix else {"": obj}
    out = {}
    for k, v in obj.items():
        key = f"{prefix}.{k}" if prefix else str(k)
        if isinstance(v, dict):
            out.update(flatten(v, key))
        else:
            out[key] = v
    return out

import unittest
from solution import flatten

class Test(unittest.TestCase):
    def test_nested(self):
        self.assertEqual(flatten({"a": {"b": 1}, "c": 2}), {"a.b": 1, "c": 2})
    def test_list(self):
        self.assertEqual(flatten({"x": [1, 2]}), {"x": [1, 2]})

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `flatten(obj, prefix="") -> dict`.

Flatten nested dicts into dotted keys. Lists are not flattened: a list value
is stored as-is. Non-dict roots return {prefix or "": obj}.


Answer:
def flatten(obj, prefix=""):
 if not isinstance(obj, dict):
 return {prefix: obj} if prefix else {"": obj}
 out = {}
 for k, v in obj.items():
 key = f"{prefix}.{k}" if prefix else str(k)
 if isinstance(v, dict):
 out.update(flatten(v, key))
 else:
 out[key] = v
 return out

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_list (test_solution.Test.test_list) ... ok
test_nested (test_solution.Test.test_nested) ... FAIL

======================================================================
FAIL: test_nested (test_solution.Test.test_nested)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-g0kfeb37\test_solution.py", line 6, in test_nested
    self.assertEqual(flatten({"a": {"b": 1}, "c": 2}), {"a.b": 1, "c": 2})
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: {'a': {'b': 1}, 'c': 2} != {'a.b': 1, 'c': 2}
- {'a': {'b': 1}, 'c': 2}
?    ^^^^^     -

+ {'a.b': 1, 'c': 2}
?    ^

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `flatten(obj, prefix="") -> dict`.

Flatten nested dicts into dotted keys. Lists are not flattened: a list value
is stored as-is. Non-dict roots return {prefix or "": obj}.

--- solution.py (buggy) ---
def flatten(obj, prefix=""):
 return obj if isinstance(obj, dict) else {prefix: obj}

--- test_solution.py ---
import unittest
from solution import flatten

class Test(unittest.TestCase):
 def test_nested(self):
 self.assertEqual(flatten({"a": {"b": 1}, "c": 2}), {"a.b": 1, "c": 2})
 def test_list(self):
 self.assertEqual(flatten({"x": [1, 2]}), {"x": [1, 2]})

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_list (test_solution.Test.test_list) ... ok
test_nested (test_solution.Test.test_nested) ... FAIL

======================================================================
FAIL: test_nested (test_solution.Test.test_nested)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-g0kfeb37\test_solution.py", line 6, in test_nested
 self.assertEqual(flatten({"a": {"b": 1}, "c": 2}), {"a.b": 1, "c": 2})
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: {'a': {'b': 1}, 'c': 2} != {'a.b': 1, 'c': 2}
- {'a': {'b': 1}, 'c': 2}
? ^^^^^ -

+ {'a.b': 1, 'c': 2}
? ^

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)


Answer:
from collections import deque

def max_windows(xs, k):
 n = len(xs)
 if k < 1 or k > n:
 return []
 dq = deque()
 out = []
 for i, val in enumerate(xs):
 while dq and dq[0] <= i - k:
 dq.popleft()
 while dq and xs[dq[-1]] <= val:
 dq.pop()
 dq.append(i)
 if i >= k - 1:
 out.append(xs[dq[0]])
 return out

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

from collections import deque

def max_windows(xs, k):
    n = len(xs)
    if k < 1 or k > n:
        return []
    dq = deque()
    out = []
    for i, val in enumerate(xs):
        while dq and dq[0] <= i - k:
            dq.popleft()
        while dq and xs[dq[-1]] <= val:
            dq.pop()
        dq.append(i)
        if i >= k - 1:
            out.append(xs[dq[0]])
    return out

import unittest
from solution import max_windows

class Test(unittest.TestCase):
    def test_k2(self):
        self.assertEqual(max_windows([1, 3, 2, 5, 4], 2), [3, 3, 5, 5])
    def test_bad(self):
        self.assertEqual(max_windows([1, 2], 3), [])

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `max_windows(xs, k) -> list`.

For each contiguous window of length k, append the maximum. If k < 1 or
k > len(xs), return [].


Answer:
from collections import deque

def max_windows(xs, k):
 n = len(xs)
 if k < 1 or k > n:
 return []
 dq = deque()
 out = []
 for i, val in enumerate(xs):
 while dq and dq[0] <= i - k:
 dq.popleft()
 while dq and xs[dq[-1]] <= val:
 dq.pop()
 dq.append(i)
 if i >= k - 1:
 out.append(xs[dq[0]])
 return out

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_bad (test_solution.Test.test_bad) ... ok
test_k2 (test_solution.Test.test_k2) ... FAIL

======================================================================
FAIL: test_k2 (test_solution.Test.test_k2)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-8jkaanmn\test_solution.py", line 6, in test_k2
    self.assertEqual(max_windows([1, 3, 2, 5, 4], 2), [3, 3, 5, 5])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [5, 5, 5, 5] != [3, 3, 5, 5]

First differing element 0:
5
3

- [5, 5, 5, 5]
+ [3, 3, 5, 5]

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)

Repeats the global max instead of each window max.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `max_windows(xs, k) -> list`.

For each contiguous window of length k, append the maximum. If k < 1 or
k > len(xs), return [].

--- solution.py (buggy) ---
def max_windows(xs, k):
 return [max(xs)] * max(0, len(xs) - k + 1)

--- test_solution.py ---
import unittest
from solution import max_windows

class Test(unittest.TestCase):
 def test_k2(self):
 self.assertEqual(max_windows([1, 3, 2, 5, 4], 2), [3, 3, 5, 5])
 def test_bad(self):
 self.assertEqual(max_windows([1, 2], 3), [])

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_bad (test_solution.Test.test_bad) ... ok
test_k2 (test_solution.Test.test_k2) ... FAIL

======================================================================
FAIL: test_k2 (test_solution.Test.test_k2)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-8jkaanmn\test_solution.py", line 6, in test_k2
 self.assertEqual(max_windows([1, 3, 2, 5, 4], 2), [3, 3, 5, 5])
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [5, 5, 5, 5] != [3, 3, 5, 5]

First differing element 0:
5
3

- [5, 5, 5, 5]
+ [3, 3, 5, 5]

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)


Answer:
def nested_body_count(n):
 return n * (n + 1) // 2

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def nested_body_count(n):
    return n * (n + 1) // 2

import unittest
from solution import nested_body_count

class Test(unittest.TestCase):
    def test_n4(self):
        self.assertEqual(nested_body_count(4), 10)
    def test_n1(self):
        self.assertEqual(nested_body_count(1), 1)
    def test_n0(self):
        self.assertEqual(nested_body_count(0), 0)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `nested_body_count(n: int) -> int`.

A loop i from 1..n inclusive, inner j from 1..i inclusive, each inner body
increments a counter once. Return that count. This is a checkable complexity
exercise, not a timing benchmark.


Answer:
def nested_body_count(n):
 return n * (n + 1) // 2

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 3, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_n0 (test_solution.Test.test_n0) ... ok
test_n1 (test_solution.Test.test_n1) ... ok
test_n4 (test_solution.Test.test_n4) ... FAIL

======================================================================
FAIL: test_n4 (test_solution.Test.test_n4)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-yexpjyv_\test_solution.py", line 6, in test_n4
    self.assertEqual(nested_body_count(4), 10)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 16 != 10

----------------------------------------------------------------------
Ran 3 tests in 0.000s

FAILED (failures=1)

def nested_body_count(n):
    return n * n

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `nested_body_count(n: int) -> int`.

A loop i from 1..n inclusive, inner j from 1..i inclusive, each inner body
increments a counter once. Return that count. This is a checkable complexity
exercise, not a timing benchmark.

--- solution.py (buggy) ---
def nested_body_count(n):
 return n * n

--- test_solution.py ---
import unittest
from solution import nested_body_count

class Test(unittest.TestCase):
 def test_n4(self):
 self.assertEqual(nested_body_count(4), 10)
 def test_n1(self):
 self.assertEqual(nested_body_count(1), 1)
 def test_n0(self):
 self.assertEqual(nested_body_count(0), 0)

--- failure ---
OPEN_REASON_RESULT {"tests_run": 3, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_n0 (test_solution.Test.test_n0) ... ok
test_n1 (test_solution.Test.test_n1) ... ok
test_n4 (test_solution.Test.test_n4) ... FAIL

======================================================================
FAIL: test_n4 (test_solution.Test.test_n4)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-yexpjyv_\test_solution.py", line 6, in test_n4
 self.assertEqual(nested_body_count(4), 10)
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 16 != 10

----------------------------------------------------------------------
Ran 3 tests in 0.000s

FAILED (failures=1)


Answer:
def normalize_name(text):
 return " ".join(text.split()).lower()

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def normalize_name(text):
    return " ".join(text.split()).lower()

import unittest
from solution import normalize_name

class Test(unittest.TestCase):
    def test_spaces(self):
        self.assertEqual(normalize_name("  Ada   Lovelace "), "ada lovelace")
    def test_empty(self):
        self.assertEqual(normalize_name("   "), "")

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Refactor the inlined logic into `normalize_name(text: str) -> str`.

Trim, collapse internal whitespace to single spaces, and lowercase. Empty
after trim is "". Callers will import normalize_name.


Answer:
def normalize_name(text):
 return " ".join(text.split()).lower()

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_empty (test_solution.Test.test_empty) ... ok
test_spaces (test_solution.Test.test_spaces) ... FAIL

======================================================================
FAIL: test_spaces (test_solution.Test.test_spaces)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-9sphhqfu\test_solution.py", line 6, in test_spaces
    self.assertEqual(normalize_name("  Ada   Lovelace "), "ada lovelace")
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 'ada   lovelace' != 'ada lovelace'
- ada   lovelace
?    --
+ ada lovelace

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Refactor the inlined logic into `normalize_name(text: str) -> str`.

Trim, collapse internal whitespace to single spaces, and lowercase. Empty
after trim is "". Callers will import normalize_name.

--- solution.py (buggy) ---
def normalize_name(text):
 return text.strip().lower()

--- test_solution.py ---
import unittest
from solution import normalize_name

class Test(unittest.TestCase):
 def test_spaces(self):
 self.assertEqual(normalize_name(" Ada Lovelace "), "ada lovelace")
 def test_empty(self):
 self.assertEqual(normalize_name(" "), "")

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_empty (test_solution.Test.test_empty) ... ok
test_spaces (test_solution.Test.test_spaces) ... FAIL

======================================================================
FAIL: test_spaces (test_solution.Test.test_spaces)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-9sphhqfu\test_solution.py", line 6, in test_spaces
 self.assertEqual(normalize_name(" Ada Lovelace "), "ada lovelace")
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 'ada lovelace' != 'ada lovelace'
- ada lovelace
? --
+ ada lovelace

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)


Answer:
def bisect_left(xs, target):
 lo, hi = 0, len(xs)
 while lo < hi:
 mid = (lo + hi) // 2
 if xs[mid] < target:
 lo = mid + 1
 else:
 hi = mid
 return lo

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def bisect_left(xs, target):
    lo, hi = 0, len(xs)
    while lo < hi:
        mid = (lo + hi) // 2
        if xs[mid] < target:
            lo = mid + 1
        else:
            hi = mid
    return lo

import unittest
from solution import bisect_left

class Test(unittest.TestCase):
    def test_dup(self):
        self.assertEqual(bisect_left([1, 2, 2, 3], 2), 1)
    def test_end(self):
        self.assertEqual(bisect_left([1, 2], 5), 2)
    def test_empty(self):
        self.assertEqual(bisect_left([], 1), 0)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Complete `bisect_left(xs, target) -> int` for a sorted list `xs`.

Return the insertion index of `target` (first position where all earlier
elements are strictly less). Empty list returns 0.

test_dup (test_solution.Test.test_dup) ... ok
test_empty (test_solution.Test.test_empty) ... ok
test_end (test_solution.Test.test_end) ... ok

----------------------------------------------------------------------
Ran 3 tests in 0.000s

OK


Answer:
def fizzbuzz(n):
 out = []
 for i in range(1, n + 1):
 if i % 15 == 0:
 out.append("FizzBuzz")
 elif i % 3 == 0:
 out.append("Fizz")
 elif i % 5 == 0:
 out.append("Buzz")
 else:
 out.append(str(i))
 return out

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def fizzbuzz(n):
    out = []
    for i in range(1, n + 1):
        if i % 15 == 0:
            out.append("FizzBuzz")
        elif i % 3 == 0:
            out.append("Fizz")
        elif i % 5 == 0:
            out.append("Buzz")
        else:
            out.append(str(i))
    return out

import unittest
from solution import fizzbuzz

class Test(unittest.TestCase):
    def test_15(self):
        got = fizzbuzz(15)
        self.assertEqual(got[2], "Fizz")
        self.assertEqual(got[4], "Buzz")
        self.assertEqual(got[14], "FizzBuzz")
        self.assertEqual(got[0], "1")
    def test_len(self):
        self.assertEqual(len(fizzbuzz(0)), 0)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `fizzbuzz(n) -> list[str]` AND keep the unittest class so that
n=1..15 is fully specified: multiples of 15 are 'FizzBuzz', of 3 'Fizz', of 5
'Buzz', else the decimal string.


Answer:
def fizzbuzz(n):
 out = []
 for i in range(1, n + 1):
 if i % 15 == 0:
 out.append("FizzBuzz")
 elif i % 3 == 0:
 out.append("Fizz")
 elif i % 5 == 0:
 out.append("Buzz")
 else:
 out.append(str(i))
 return out

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_15 (test_solution.Test.test_15) ... FAIL
test_len (test_solution.Test.test_len) ... ok

======================================================================
FAIL: test_15 (test_solution.Test.test_15)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-0mqvzxsp\test_solution.py", line 7, in test_15
    self.assertEqual(got[2], "Fizz")
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: '3' != 'Fizz'
- 3
+ Fizz

----------------------------------------------------------------------
Ran 2 tests in 0.000s

FAILED (failures=1)

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `fizzbuzz(n) -> list[str]` AND keep the unittest class so that
n=1..15 is fully specified: multiples of 15 are 'FizzBuzz', of 3 'Fizz', of 5
'Buzz', else the decimal string.

--- solution.py (buggy) ---
def fizzbuzz(n):
 return [str(i) for i in range(1, n + 1)]

--- test_solution.py ---
import unittest
from solution import fizzbuzz

class Test(unittest.TestCase):
 def test_15(self):
 got = fizzbuzz(15)
 self.assertEqual(got[2], "Fizz")
 self.assertEqual(got[4], "Buzz")
 self.assertEqual(got[14], "FizzBuzz")
 self.assertEqual(got[0], "1")
 def test_len(self):
 self.assertEqual(len(fizzbuzz(0)), 0)

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_15 (test_solution.Test.test_15) ... FAIL
test_len (test_solution.Test.test_len) ... ok

======================================================================
FAIL: test_15 (test_solution.Test.test_15)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-0mqvzxsp\test_solution.py", line 7, in test_15
 self.assertEqual(got[2], "Fizz")
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
AssertionError: '3' != 'Fizz'
- 3
+ Fizz

----------------------------------------------------------------------
Ran 2 tests in 0.000s

FAILED (failures=1)


Answer:
def first_n(xs, n):
 if n < 0:
 raise ValueError("n")
 return xs[:n]

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def first_n(xs, n):
    if n < 0:
        raise ValueError("n")
    return xs[:n]

import unittest
from solution import first_n

class Test(unittest.TestCase):
    def test_short(self):
        self.assertEqual(first_n([1, 2, 3], 2), [1, 2])
    def test_over(self):
        self.assertEqual(first_n([1], 5), [1])
    def test_neg(self):
        with self.assertRaises(ValueError):
            first_n([1], -1)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
The intended spec: `first_n(xs, n)` returns the first n items, or all of
xs if n >= len(xs). n < 0 raises ValueError. Fix the buggy body.

test_neg (test_solution.Test.test_neg) ... ok
test_over (test_solution.Test.test_over) ... ok
test_short (test_solution.Test.test_short) ... ok

----------------------------------------------------------------------
Ran 3 tests in 0.000s

OK


Answer:
def first_n(xs, n):
 if n < 0:
 raise ValueError("n")
 return xs[:n]

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 3, "failures": 2, "errors": 0, "skipped": 0, "passed": false}

test_neg (test_solution.Test.test_neg) ... FAIL
test_over (test_solution.Test.test_over) ... ok
test_short (test_solution.Test.test_short) ... FAIL

======================================================================
FAIL: test_neg (test_solution.Test.test_neg)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-xblgdj5f\test_solution.py", line 10, in test_neg
    with self.assertRaises(ValueError):
         ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
AssertionError: ValueError not raised

======================================================================
FAIL: test_short (test_solution.Test.test_short)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-xblgdj5f\test_solution.py", line 6, in test_short
    self.assertEqual(first_n([1, 2, 3], 2), [1, 2])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [1] != [1, 2]

Second list contains 1 additional elements.
First extra element 1:
2

- [1]
+ [1, 2]

----------------------------------------------------------------------
Ran 3 tests in 0.001s

FAILED (failures=2)

def first_n(xs, n):
    return xs[: n - 1]

Uses n-1 as the slice end and ignores negative n.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

The intended spec: `first_n(xs, n)` returns the first n items, or all of
xs if n >= len(xs). n < 0 raises ValueError. Fix the buggy body.

--- solution.py (buggy) ---
def first_n(xs, n):
 return xs[: n - 1]

--- test_solution.py ---
import unittest
from solution import first_n

class Test(unittest.TestCase):
 def test_short(self):
 self.assertEqual(first_n([1, 2, 3], 2), [1, 2])
 def test_over(self):
 self.assertEqual(first_n([1], 5), [1])
 def test_neg(self):
 with self.assertRaises(ValueError):
 first_n([1], -1)

--- failure ---
OPEN_REASON_RESULT {"tests_run": 3, "failures": 2, "errors": 0, "skipped": 0, "passed": false}

test_neg (test_solution.Test.test_neg) ... FAIL
test_over (test_solution.Test.test_over) ... ok
test_short (test_solution.Test.test_short) ... FAIL

======================================================================
FAIL: test_neg (test_solution.Test.test_neg)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-xblgdj5f\test_solution.py", line 10, in test_neg
 with self.assertRaises(ValueError):
 ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
AssertionError: ValueError not raised

======================================================================
FAIL: test_short (test_solution.Test.test_short)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-xblgdj5f\test_solution.py", line 6, in test_short
 self.assertEqual(first_n([1, 2, 3], 2), [1, 2])
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [1] != [1, 2]

Second list contains 1 additional elements.
First extra element 1:
2

- [1]
+ [1, 2]

----------------------------------------------------------------------
Ran 3 tests in 0.001s

FAILED (failures=2)


Answer:
def components(n, edges):
 parent = list(range(n))

 def find(x):
 while parent[x] != x:
 parent[x] = parent[parent[x]]
 x = parent[x]
 return x

 def union(a, b):
 ra, rb = find(a), find(b)
 if ra != rb:
 parent[rb] = ra

 for a, b in edges:
 union(a, b)
 return len({find(i) for i in range(n)})

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def components(n, edges):
    parent = list(range(n))

    def find(x):
        while parent[x] != x:
            parent[x] = parent[parent[x]]
            x = parent[x]
        return x

    def union(a, b):
        ra, rb = find(a), find(b)
        if ra != rb:
            parent[rb] = ra

    for a, b in edges:
        union(a, b)
    return len({find(i) for i in range(n)})

import unittest
from solution import components

class Test(unittest.TestCase):
    def test_two(self):
        self.assertEqual(components(4, [(0, 1), (1, 0), (2, 3)]), 2)
    def test_isolated(self):
        self.assertEqual(components(3, []), 3)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `components(n, edges) -> int`.

Nodes are 0..n-1. `edges` is a list of undirected pairs. Return the number of
connected components (isolated nodes count).


Answer:
def components(n, edges):
 parent = list(range(n))

 def find(x):
 while parent[x] != x:
 parent[x] = parent[parent[x]]
 x = parent[x]
 return x

 def union(a, b):
 ra, rb = find(a), find(b)
 if ra != rb:
 parent[rb] = ra

 for a, b in edges:
 union(a, b)
 return len({find(i) for i in range(n)})

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_isolated (test_solution.Test.test_isolated) ... ok
test_two (test_solution.Test.test_two) ... FAIL

======================================================================
FAIL: test_two (test_solution.Test.test_two)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-b7fw_ep9\test_solution.py", line 6, in test_two
    self.assertEqual(components(4, [(0, 1), (1, 0), (2, 3)]), 2)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1 != 2

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)

Treats every edge as merging two unique components.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `components(n, edges) -> int`.

Nodes are 0..n-1. `edges` is a list of undirected pairs. Return the number of
connected components (isolated nodes count).

--- solution.py (buggy) ---
def components(n, edges):
 return n - len(edges)

--- test_solution.py ---
import unittest
from solution import components

class Test(unittest.TestCase):
 def test_two(self):
 self.assertEqual(components(4, [(0, 1), (1, 0), (2, 3)]), 2)
 def test_isolated(self):
 self.assertEqual(components(3, []), 3)

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_isolated (test_solution.Test.test_isolated) ... ok
test_two (test_solution.Test.test_two) ... FAIL

======================================================================
FAIL: test_two (test_solution.Test.test_two)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-b7fw_ep9\test_solution.py", line 6, in test_two
 self.assertEqual(components(4, [(0, 1), (1, 0), (2, 3)]), 2)
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1 != 2

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)


Answer:
def kth_smallest(xs, k):
 if k < 1 or k > len(xs):
 raise IndexError("k")
 return sorted(xs)[k - 1]

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def kth_smallest(xs, k):
    if k < 1 or k > len(xs):
        raise IndexError("k")
    return sorted(xs)[k - 1]

import unittest
from solution import kth_smallest

class Test(unittest.TestCase):
    def test_k(self):
        self.assertEqual(kth_smallest([7, 1, 5, 3], 2), 3)
    def test_bad(self):
        with self.assertRaises(IndexError):
            kth_smallest([1], 2)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `kth_smallest(xs, k) -> int`.

1-based k. Return the k-th smallest element of xs (distinctness not required).
Raise IndexError if k is out of range. You may sort.


Answer:
def kth_smallest(xs, k):
 if k < 1 or k > len(xs):
 raise IndexError("k")
 return sorted(xs)[k - 1]

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_bad (test_solution.Test.test_bad) ... ok
test_k (test_solution.Test.test_k) ... FAIL

======================================================================
FAIL: test_k (test_solution.Test.test_k)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-em7qhwxo\test_solution.py", line 6, in test_k
    self.assertEqual(kth_smallest([7, 1, 5, 3], 2), 3)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 5 != 3

----------------------------------------------------------------------
Ran 2 tests in 0.000s

FAILED (failures=1)

def kth_smallest(xs, k):
    return xs[k]

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `kth_smallest(xs, k) -> int`.

1-based k. Return the k-th smallest element of xs (distinctness not required).
Raise IndexError if k is out of range. You may sort.

--- solution.py (buggy) ---
def kth_smallest(xs, k):
 return xs[k]

--- test_solution.py ---
import unittest
from solution import kth_smallest

class Test(unittest.TestCase):
 def test_k(self):
 self.assertEqual(kth_smallest([7, 1, 5, 3], 2), 3)
 def test_bad(self):
 with self.assertRaises(IndexError):
 kth_smallest([1], 2)

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_bad (test_solution.Test.test_bad) ... ok
test_k (test_solution.Test.test_k) ... FAIL

======================================================================
FAIL: test_k (test_solution.Test.test_k)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-em7qhwxo\test_solution.py", line 6, in test_k
 self.assertEqual(kth_smallest([7, 1, 5, 3], 2), 3)
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 5 != 3

----------------------------------------------------------------------
Ran 2 tests in 0.000s

FAILED (failures=1)


Answer:
import hashlib

def bucket(key, n):
 digest = hashlib.md5(key.encode("utf-8")).hexdigest()
 return int(digest[:8], 16) % n

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

import hashlib

def bucket(key, n):
    digest = hashlib.md5(key.encode("utf-8")).hexdigest()
    return int(digest[:8], 16) % n

import unittest
from solution import bucket

class Test(unittest.TestCase):
    def test_range(self):
        b = bucket("alpha", 10)
        self.assertGreaterEqual(b, 0)
        self.assertLess(b, 10)
    def test_stable(self):
        self.assertEqual(bucket("alpha", 10), bucket("alpha", 10))
    def test_known(self):
        import hashlib
        expected = int(hashlib.md5(b"alpha").hexdigest()[:8], 16) % 10
        self.assertEqual(bucket("alpha", 10), expected)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `bucket(key: str, n: int) -> int`.

Return a bucket in 0..n-1 using Python's stable hash of the UTF-8 bytes via
hashlib.md5 (first 8 hex digits as int) so tests are deterministic across
processes. n > 0.

test_known (test_solution.Test.test_known) ... ok
test_range (test_solution.Test.test_range) ... ok
test_stable (test_solution.Test.test_stable) ... ok

----------------------------------------------------------------------
Ran 3 tests in 0.000s

OK


Answer:
import hashlib

def bucket(key, n):
 digest = hashlib.md5(key.encode("utf-8")).hexdigest()
 return int(digest[:8], 16) % n

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 3, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_known (test_solution.Test.test_known) ... FAIL
test_range (test_solution.Test.test_range) ... ok
test_stable (test_solution.Test.test_stable) ... ok

======================================================================
FAIL: test_known (test_solution.Test.test_known)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-ro9djynm\test_solution.py", line 14, in test_known
    self.assertEqual(bucket("alpha", 10), expected)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 5 != 7

----------------------------------------------------------------------
Ran 3 tests in 0.004s

FAILED (failures=1)

def bucket(key, n):
    return len(key) % n

Uses string length, so different keys collide by design.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `bucket(key: str, n: int) -> int`.

Return a bucket in 0..n-1 using Python's stable hash of the UTF-8 bytes via
hashlib.md5 (first 8 hex digits as int) so tests are deterministic across
processes. n > 0.

--- solution.py (buggy) ---
def bucket(key, n):
 return len(key) % n

--- test_solution.py ---
import unittest
from solution import bucket

class Test(unittest.TestCase):
 def test_range(self):
 b = bucket("alpha", 10)
 self.assertGreaterEqual(b, 0)
 self.assertLess(b, 10)
 def test_stable(self):
 self.assertEqual(bucket("alpha", 10), bucket("alpha", 10))
 def test_known(self):
 import hashlib
 expected = int(hashlib.md5(b"alpha").hexdigest()[:8], 16) % 10
 self.assertEqual(bucket("alpha", 10), expected)

--- failure ---
OPEN_REASON_RESULT {"tests_run": 3, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_known (test_solution.Test.test_known) ... FAIL
test_range (test_solution.Test.test_range) ... ok
test_stable (test_solution.Test.test_stable) ... ok

======================================================================
FAIL: test_known (test_solution.Test.test_known)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-ro9djynm\test_solution.py", line 14, in test_known
 self.assertEqual(bucket("alpha", 10), expected)
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 5 != 7

----------------------------------------------------------------------
Ran 3 tests in 0.004s

FAILED (failures=1)


Answer:
def second_pass(xs):
 data = list(xs)
 return data, list(data)

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def second_pass(xs):
    data = list(xs)
    return data, list(data)

import unittest
from solution import second_pass

class Test(unittest.TestCase):
    def test_gen(self):
        a, b = second_pass(i for i in range(3))
        self.assertEqual(a, [0, 1, 2])
        self.assertEqual(b, [0, 1, 2])
    def test_list(self):
        src = [1, 2]
        a, b = second_pass(src)
        self.assertEqual(a, [1, 2])
        self.assertEqual(src, [1, 2])

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `second_pass(xs) -> tuple`.

Consume an iterable twice: return (list first pass, list second pass) with
equal contents even if `xs` is a one-shot iterator. Do not mutate a list
input in place.


Answer:
def second_pass(xs):
 data = list(xs)
 return data, list(data)

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_gen (test_solution.Test.test_gen) ... FAIL
test_list (test_solution.Test.test_list) ... ok

======================================================================
FAIL: test_gen (test_solution.Test.test_gen)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-s0pkcqax\test_solution.py", line 8, in test_gen
    self.assertEqual(b, [0, 1, 2])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
AssertionError: Lists differ: [] != [0, 1, 2]

Second list contains 3 additional elements.
First extra element 0:
0

- []
+ [0, 1, 2]

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)

Second list(xs) on a generator is empty.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `second_pass(xs) -> tuple`.

Consume an iterable twice: return (list first pass, list second pass) with
equal contents even if `xs` is a one-shot iterator. Do not mutate a list
input in place.

--- solution.py (buggy) ---
def second_pass(xs):
 return list(xs), list(xs)

--- test_solution.py ---
import unittest
from solution import second_pass

class Test(unittest.TestCase):
 def test_gen(self):
 a, b = second_pass(i for i in range(3))
 self.assertEqual(a, [0, 1, 2])
 self.assertEqual(b, [0, 1, 2])
 def test_list(self):
 src = [1, 2]
 a, b = second_pass(src)
 self.assertEqual(a, [1, 2])
 self.assertEqual(src, [1, 2])

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_gen (test_solution.Test.test_gen) ... FAIL
test_list (test_solution.Test.test_list) ... ok

======================================================================
FAIL: test_gen (test_solution.Test.test_gen)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-s0pkcqax\test_solution.py", line 8, in test_gen
 self.assertEqual(b, [0, 1, 2])
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^
AssertionError: Lists differ: [] != [0, 1, 2]

Second list contains 3 additional elements.
First extra element 0:
0

- []
+ [0, 1, 2]

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)


Answer:
import tempfile
from pathlib import Path

def line_count(text):
 with tempfile.NamedTemporaryFile("w", encoding="utf-8", delete=False) as fh:
 fh.write(text)
 path = fh.name
 try:
 data = Path(path).read_text(encoding="utf-8")
 if data == "":
 return 0
 return len(data.splitlines())
 finally:
 Path(path).unlink(missing_ok=True)

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

import tempfile
from pathlib import Path

def line_count(text):
    with tempfile.NamedTemporaryFile("w", encoding="utf-8", delete=False) as fh:
        fh.write(text)
        path = fh.name
    try:
        data = Path(path).read_text(encoding="utf-8")
        if data == "":
            return 0
        return len(data.splitlines())
    finally:
        Path(path).unlink(missing_ok=True)

import unittest
from solution import line_count

class Test(unittest.TestCase):
    def test_two(self):
        self.assertEqual(line_count("a\nb"), 2)
    def test_empty(self):
        self.assertEqual(line_count(""), 0)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `line_count(text: str) -> int` by writing `text` to a temp file
with UTF-8, reading it back, and counting splitlines(). Empty text is 0 lines
if it has no newline and no characters; a single newline is 1 empty line
(`splitlines` behaviour).


Answer:
import tempfile
from pathlib import Path

def line_count(text):
 with tempfile.NamedTemporaryFile("w", encoding="utf-8", delete=False) as fh:
 fh.write(text)
 path = fh.name
 try:
 data = Path(path).read_text(encoding="utf-8")
 if data == "":
 return 0
 return len(data.splitlines())
 finally:
 Path(path).unlink(missing_ok=True)

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_empty (test_solution.Test.test_empty) ... ok
test_two (test_solution.Test.test_two) ... FAIL

======================================================================
FAIL: test_two (test_solution.Test.test_two)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-4c0mveyv\test_solution.py", line 6, in test_two
    self.assertEqual(line_count("a\nb"), 2)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1 != 2

----------------------------------------------------------------------
Ran 2 tests in 0.000s

FAILED (failures=1)

Counts newline characters, so 'a' is 0 instead of 1.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `line_count(text: str) -> int` by writing `text` to a temp file
with UTF-8, reading it back, and counting splitlines(). Empty text is 0 lines
if it has no newline and no characters; a single newline is 1 empty line
(`splitlines` behaviour).

--- solution.py (buggy) ---
def line_count(text):
 return text.count("\n")

--- test_solution.py ---
import unittest
from solution import line_count

class Test(unittest.TestCase):
 def test_two(self):
 self.assertEqual(line_count("a\nb"), 2)
 def test_empty(self):
 self.assertEqual(line_count(""), 0)

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_empty (test_solution.Test.test_empty) ... ok
test_two (test_solution.Test.test_two) ... FAIL

======================================================================
FAIL: test_two (test_solution.Test.test_two)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-4c0mveyv\test_solution.py", line 6, in test_two
 self.assertEqual(line_count("a\nb"), 2)
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: 1 != 2

----------------------------------------------------------------------
Ran 2 tests in 0.000s

FAILED (failures=1)


Answer:
def once(fn):
 state = {"value": None, "done": False}

 def wrapper(*args, **kwargs):
 if not state["done"]:
 state["value"] = fn(*args, **kwargs)
 state["done"] = True
 wrapper.called = True
 return state["value"]

 wrapper.called = False
 return wrapper

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def once(fn):
    state = {"value": None, "done": False}

    def wrapper(*args, **kwargs):
        if not state["done"]:
            state["value"] = fn(*args, **kwargs)
            state["done"] = True
            wrapper.called = True
        return state["value"]

    wrapper.called = False
    return wrapper

import unittest
from solution import once

class Test(unittest.TestCase):
    def test_once(self):
        n = {"c": 0}
        def f():
            n["c"] += 1
            return n["c"]
        g = once(f)
        self.assertFalse(g.called)
        self.assertEqual(g(), 1)
        self.assertEqual(g(), 1)
        self.assertTrue(g.called)
        self.assertEqual(n["c"], 1)

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `once(fn)` returning a wrapper that calls `fn` at most once and
reuses the first return value. The wrapper must have a `.called` bool.


Answer:
def once(fn):
 state = {"value": None, "done": False}

 def wrapper(*args, **kwargs):
 if not state["done"]:
 state["value"] = fn(*args, **kwargs)
 state["done"] = True
 wrapper.called = True
 return state["value"]

 wrapper.called = False
 return wrapper

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 1, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_once (test_solution.Test.test_once) ... FAIL

======================================================================
FAIL: test_once (test_solution.Test.test_once)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-p6egh8bt\test_solution.py", line 13, in test_once
    self.assertEqual(g(), 1)
    ~~~~~~~~~~~~~~~~^^^^^^^^
AssertionError: 2 != 1

----------------------------------------------------------------------
Ran 1 test in 0.000s

FAILED (failures=1)

Calls fn every time and never sets called.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `once(fn)` returning a wrapper that calls `fn` at most once and
reuses the first return value. The wrapper must have a `.called` bool.

--- solution.py (buggy) ---
def once(fn):
 def wrapper(*args, **kwargs):
 return fn(*args, **kwargs)
 wrapper.called = False
 return wrapper

--- test_solution.py ---
import unittest
from solution import once

class Test(unittest.TestCase):
 def test_once(self):
 n = {"c": 0}
 def f():
 n["c"] += 1
 return n["c"]
 g = once(f)
 self.assertFalse(g.called)
 self.assertEqual(g(), 1)
 self.assertEqual(g(), 1)
 self.assertTrue(g.called)
 self.assertEqual(n["c"], 1)

--- failure ---
OPEN_REASON_RESULT {"tests_run": 1, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_once (test_solution.Test.test_once) ... FAIL

======================================================================
FAIL: test_once (test_solution.Test.test_once)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-p6egh8bt\test_solution.py", line 13, in test_once
 self.assertEqual(g(), 1)
 ~~~~~~~~~~~~~~~~^^^^^^^^
AssertionError: 2 != 1

----------------------------------------------------------------------
Ran 1 test in 0.000s

FAILED (failures=1)


Answer:
def matmul(a, b):
 if not a or not b:
 raise ValueError("empty")
 n = len(a[0])
 if any(len(row) != n for row in a):
 raise ValueError("ragged a")
 p = len(b[0])
 if any(len(row) != p for row in b):
 raise ValueError("ragged b")
 if len(b) != n:
 raise ValueError("shape")
 out = []
 for i in range(len(a)):
 row = []
 for j in range(p):
 s = 0
 for k in range(n):
 s += a[i][k] * b[k][j]
 row.append(s)
 out.append(row)
 return out

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def matmul(a, b):
    if not a or not b:
        raise ValueError("empty")
    n = len(a[0])
    if any(len(row) != n for row in a):
        raise ValueError("ragged a")
    p = len(b[0])
    if any(len(row) != p for row in b):
        raise ValueError("ragged b")
    if len(b) != n:
        raise ValueError("shape")
    out = []
    for i in range(len(a)):
        row = []
        for j in range(p):
            s = 0
            for k in range(n):
                s += a[i][k] * b[k][j]
            row.append(s)
        out.append(row)
    return out

import unittest
from solution import matmul

class Test(unittest.TestCase):
    def test_2x2(self):
        self.assertEqual(matmul([[1, 2], [3, 4]], [[5, 6], [7, 8]]), [[19, 22], [43, 50]])
    def test_shape(self):
        with self.assertRaises(ValueError):
            matmul([[1, 2]], [[1], [2], [3]])

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `matmul(a, b)` for dense lists of lists of ints.

a is m×n, b is n×p. Return m×p. Raise ValueError on shape mismatch or empty
outer list.


Answer:
def matmul(a, b):
 if not a or not b:
 raise ValueError("empty")
 n = len(a[0])
 if any(len(row) != n for row in a):
 raise ValueError("ragged a")
 p = len(b[0])
 if any(len(row) != p for row in b):
 raise ValueError("ragged b")
 if len(b) != n:
 raise ValueError("shape")
 out = []
 for i in range(len(a)):
 row = []
 for j in range(p):
 s = 0
 for k in range(n):
 s += a[i][k] * b[k][j]
 row.append(s)
 out.append(row)
 return out

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 2, "errors": 0, "skipped": 0, "passed": false}

test_2x2 (test_solution.Test.test_2x2) ... FAIL
test_shape (test_solution.Test.test_shape) ... FAIL

======================================================================
FAIL: test_2x2 (test_solution.Test.test_2x2)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-_rfo9wd3\test_solution.py", line 6, in test_2x2
    self.assertEqual(matmul([[1, 2], [3, 4]], [[5, 6], [7, 8]]), [[19, 22], [43, 50]])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [[1, 2], [3, 4]] != [[19, 22], [43, 50]]

First differing element 0:
[1, 2]
[19, 22]

- [[1, 2], [3, 4]]
?              ^

+ [[19, 22], [43, 50]]
?    +  +     +   ^^

======================================================================
FAIL: test_shape (test_solution.Test.test_shape)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-_rfo9wd3\test_solution.py", line 8, in test_shape
    with self.assertRaises(ValueError):
         ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
AssertionError: ValueError not raised

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=2)

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `matmul(a, b)` for dense lists of lists of ints.

a is m×n, b is n×p. Return m×p. Raise ValueError on shape mismatch or empty
outer list.

--- solution.py (buggy) ---
def matmul(a, b):
 return a

--- test_solution.py ---
import unittest
from solution import matmul

class Test(unittest.TestCase):
 def test_2x2(self):
 self.assertEqual(matmul([[1, 2], [3, 4]], [[5, 6], [7, 8]]), [[19, 22], [43, 50]])
 def test_shape(self):
 with self.assertRaises(ValueError):
 matmul([[1, 2]], [[1], [2], [3]])

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 2, "errors": 0, "skipped": 0, "passed": false}

test_2x2 (test_solution.Test.test_2x2) ... FAIL
test_shape (test_solution.Test.test_shape) ... FAIL

======================================================================
FAIL: test_2x2 (test_solution.Test.test_2x2)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-_rfo9wd3\test_solution.py", line 6, in test_2x2
 self.assertEqual(matmul([[1, 2], [3, 4]], [[5, 6], [7, 8]]), [[19, 22], [43, 50]])
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [[1, 2], [3, 4]] != [[19, 22], [43, 50]]

First differing element 0:
[1, 2]
[19, 22]

- [[1, 2], [3, 4]]
? ^

+ [[19, 22], [43, 50]]
? + + + ^^

======================================================================
FAIL: test_shape (test_solution.Test.test_shape)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-_rfo9wd3\test_solution.py", line 8, in test_shape
 with self.assertRaises(ValueError):
 ~~~~~~~~~~~~~~~~~^^^^^^^^^^^^
AssertionError: ValueError not raised

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=2)


Answer:
import re

def local_parts(text):
 pat = re.compile(r"\b([A-Za-z0-9._-]+)@([A-Za-z0-9._-]+\.[A-Za-z0-9._-]+)\b")
 seen = []
 found = set()
 for local, _dom in pat.findall(text):
 if local not in found:
 found.add(local)
 seen.append(local)
 return seen

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

import re

def local_parts(text):
    pat = re.compile(r"\b([A-Za-z0-9._-]+)@([A-Za-z0-9._-]+\.[A-Za-z0-9._-]+)\b")
    seen = []
    found = set()
    for local, _dom in pat.findall(text):
        if local not in found:
            found.add(local)
            seen.append(local)
    return seen

import unittest
from solution import local_parts

class Test(unittest.TestCase):
    def test_two(self):
        self.assertEqual(
            local_parts("mail ada@ex.org then ada@ex.org and bob@site.co.uk"),
            ["ada", "bob"],
        )
    def test_none(self):
        self.assertEqual(local_parts("no mail here"), [])

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `local_parts(text: str) -> list[str]`.

Find emails of the form local@domain where local and domain are nonempty
runs of [A-Za-z0-9._-], domain contains at least one dot, and return unique
local parts in first-seen order.


Answer:
def select(rows, pred, cols):
 out = []
 for row in rows:
 if pred(row):
 out.append({c: row[c] for c in cols})
 return out

Use only the Python standard library unless the prompt says otherwise.

The hidden tests in test_solution.py must pass.

def select(rows, pred, cols):
    out = []
    for row in rows:
        if pred(row):
            out.append({c: row[c] for c in cols})
    return out

import unittest
from solution import select

class Test(unittest.TestCase):
    def test_filter(self):
        rows = [{"n": "a", "v": 1}, {"n": "b", "v": 2}]
        got = select(rows, lambda r: r["v"] > 1, ["n"])
        self.assertEqual(got, [{"n": "b"}])
    def test_none(self):
        self.assertEqual(select([], lambda r: True, ["n"]), [])

Read the specification
Implement the function or class
Satisfy the tests

Prompt:
Implement `select(rows, pred, cols) -> list`.

`rows` is a list of dicts. `pred(row)` is a callable. `cols` is a list of keys.
Return dicts with only those keys, in input order, for rows where pred is true.


Answer:
def select(rows, pred, cols):
 out = []
 for row in rows:
 if pred(row):
 out.append({c: row[c] for c in cols})
 return out

Do not weaken or delete tests
Keep the public API

Output:
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_filter (test_solution.Test.test_filter) ... FAIL
test_none (test_solution.Test.test_none) ... ok

======================================================================
FAIL: test_filter (test_solution.Test.test_filter)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-2eo40i_8\test_solution.py", line 8, in test_filter
    self.assertEqual(got, [{"n": "b"}])
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [{'n': 'a', 'v': 1}, {'n': 'b', 'v': 2}] != [{'n': 'b'}]

First differing element 0:
{'n': 'a', 'v': 1}
{'n': 'b'}

First list contains 1 additional elements.
First extra element 1:
{'n': 'b', 'v': 2}

- [{'n': 'a', 'v': 1}, {'n': 'b', 'v': 2}]
+ [{'n': 'b'}]

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)

Ignores predicate and column projection.

Reproduce the failure
Identify the defect
Apply a minimal fix
Re-run tests

Prompt:
The following Python module fails its tests. Produce a corrected solution.py that preserves the intended behaviour.

Implement `select(rows, pred, cols) -> list`.

`rows` is a list of dicts. `pred(row)` is a callable. `cols` is a list of keys.
Return dicts with only those keys, in input order, for rows where pred is true.

--- solution.py (buggy) ---
def select(rows, pred, cols):
 return rows

--- test_solution.py ---
import unittest
from solution import select

class Test(unittest.TestCase):
 def test_filter(self):
 rows = [{"n": "a", "v": 1}, {"n": "b", "v": 2}]
 got = select(rows, lambda r: r["v"] > 1, ["n"])
 self.assertEqual(got, [{"n": "b"}])
 def test_none(self):
 self.assertEqual(select([], lambda r: True, ["n"]), [])

--- failure ---
OPEN_REASON_RESULT {"tests_run": 2, "failures": 1, "errors": 0, "skipped": 0, "passed": false}

test_filter (test_solution.Test.test_filter) ... FAIL
test_none (test_solution.Test.test_none) ... ok

======================================================================
FAIL: test_filter (test_solution.Test.test_filter)
----------------------------------------------------------------------
Traceback (most recent call last):
 File "C:\Users\matth\AppData\Local\Temp\open-reason-sandbox-2eo40i_8\test_solution.py", line 8, in test_filter
 self.assertEqual(got, [{"n": "b"}])
 ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^
AssertionError: Lists differ: [{'n': 'a', 'v': 1}, {'n': 'b', 'v': 2}] != [{'n': 'b'}]

First differing element 0:
{'n': 'a', 'v': 1}
{'n': 'b'}

First list contains 1 additional elements.
First extra element 1:
{'n': 'b', 'v': 2}

- [{'n': 'a', 'v': 1}, {'n': 'b', 'v': 2}]
+ [{'n': 'b'}]

----------------------------------------------------------------------
Ran 2 tests in 0.001s

FAILED (failures=1)