OpenROAD/docs/agents/testing.md

# OpenROAD Testing Guide

OpenROAD has two types of tests: **integration tests** (Tcl) and **unit tests** (C++).

> For **where** new tests should live (the C++-first test pyramid) and **how** to
> handle DB/STA dependencies, see `testing-strategy.md`. This guide covers the
> mechanics of writing and registering a test.

## CAUTION -- Dual Registration Required

**Every new test MUST be registered in BOTH build systems. Missing either one is a build break.**

| Build System | Registration File                  | Block/Macro                 |
| ------------ | ---------------------------------- | --------------------------- |
| **CMake**    | `src/<module>/test/CMakeLists.txt` | `or_integration_tests(...)` |
| **Bazel**    | `src/<module>/test/BUILD`          | `regression_test(...)`      |

Forgetting the Bazel `BUILD` file is the most common mistake -- CMake-only registration
silently passes local `make test` but the **test will be missing from Bazel CI**.

## Integration Tests

Integration tests are Tcl scripts located at `src/<module>/test` or `src/<module>/test/tcl`.

### Running Integration Tests

`./regression` is a ctest wrapper that filters by module label.

```bash
cd src/rsz/test
./regression -R buffer_ports1   # run one test (regex match)
./regression -R "repair.*hier"  # run tests matching pattern
./regression -j4 -V             # all rsz tests, parallel, verbose

# Or equivalently from the build directory:
cd build
ctest -R "rsz\.buffer_ports1\.tcl"
```

### Creating a New Integration Test

Best practice reference: `src/rsz/test/repair_tie12_hier.tcl`

#### Issue Reproduction Tests

For issue reproductions, keep the test case minimal and focused on the failing tool behavior. When floorplanning or placement is not part of the bug, encode the small problem design directly in DEF and use `read_def` after loading the necessary LEF and Liberty files instead of running floorplanning or global placement. This keeps the test simpler and more stable across unrelated OpenROAD behavior changes. Use floorplanning or placement steps when those stages are part of the behavior under test.

#### Checklist

1. **Header comment**: First line must explain the test purpose
   ```tcl
   # [Brief description of the test]
   ```

2. **Set test name**: Used for output file generation
   ```tcl
   set test_name <integration_test_name>
   ```

3. **Output naming with `make_result_file`**: Use for temporary output files
   ```tcl
   set verilog_filename "${test_name}.v"
   set out_verilog [make_result_file $verilog_filename]
   write_verilog $out_verilog
   ```

4. **Verification with `diff_file`**: Compare against golden files
   ```tcl
   diff_file ${test_name}.vok $out_verilog
   ```

5. **Generate `<test_name>.ok` file**: Create golden test log by executing the script, redirecting stdout, and removing the openroad banner at the top.

6. **Registration (BOTH files for CMake and Bazel -- do NOT skip Bazel)**

### Test Framework Flags
- `-no_splash -no_init -exit`

### Golden File Notes
- `.ok` = log golden file (full stdout), `.vok` = verilog golden file
- **`diff_file` reports only the first difference** -- when regenerating golden files, regenerate the entire output file rather than relying on incremental diffs.

## Unit Tests

Unit tests are C++ files located at `src/<module>/test/cpp`.

### Test Registration
- CMake: `src/<module>/test/CMakeLists.txt`
- Bazel: `src/<module>/test/BUILD` or `src/<module>/test/cpp/BUILD`