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.

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

Header comment: First line must explain the test purpose
```
# [Brief description of the test]
```
Set test name: Used for output file generation
```
set test_name <integration_test_name>
```

Output naming with make_result_file: Use for temporary output files

set verilog_filename "${test_name}.v"
set out_verilog [make_result_file $verilog_filename]
write_verilog $out_verilog

Verification with diff_file: Compare against golden files
```
diff_file ${test_name}.vok $out_verilog
```
Generate <test_name>.ok file: Create golden test log by executing the script, redirecting stdout, and removing the openroad banner at the top.
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