Add pytest-xdist for parallel test execution

.github/actions/daily-perf-improver/build-steps/action.yml

@@ -21,7 +21,7 @@ runs:
       shell: bash
       run: |
         echo "=== Installing dev dependencies ===" | tee -a build-steps.log
-        pip install pytest pytest-mock memory_profiler 2>&1 | tee -a build-steps.log
+        pip install pytest pytest-mock pytest-xdist memory_profiler 2>&1 | tee -a build-steps.log
         echo "✓ Dev dependencies installed" | tee -a build-steps.log
 
     - name: Verify installation
@@ -42,7 +42,7 @@ runs:
       shell: bash
       run: |
         echo "=== Running test suite ===" | tee -a build-steps.log
-        pytest tests/ -v 2>&1 | tee -a build-steps.log
+        pytest tests/ -n auto -v 2>&1 | tee -a build-steps.log
         echo "✓ Tests completed" | tee -a build-steps.log
       # Allow build to continue even with test failures so the agent can analyze
       # failures and attempt fixes. The agent checks build-steps.log for issues.

README.md

@@ -105,6 +105,49 @@ https://controld.com/dashboard/profiles/741861frakbm/filters
 - Python 3.13+
 - `uv` (for dependency management)
 
+## Testing
+
+This project includes a comprehensive test suite to ensure code quality and correctness.
+
+### Running Tests
+
+**Basic test execution:**
+```bash
+# Install dev dependencies first
+pip install pytest pytest-mock pytest-xdist
+
+# Run all tests
+pytest tests/
+```
+
+**Parallel test execution (recommended):**
+```bash
+# Run tests in parallel using all available CPU cores
+pytest tests/ -n auto
+
+# Run with specific number of workers
+pytest tests/ -n 4
+```
+
+**Note on parallel execution:** The test suite is currently small (~78 tests, <1s execution time), so parallel execution overhead may result in longer wall-clock time compared to sequential execution. However, pytest-xdist is included for:
+- **Test isolation verification** - Ensures tests don't share state
+- **Future scalability** - As the test suite grows, parallel execution will provide significant speedups
+- **CI optimization** - May benefit from parallelization in CI environments with different characteristics
+
+### Development Workflow
+
+For active development with frequent test runs:
+```bash
+# Run tests sequentially (faster for small test suites)
+pytest tests/ -v
+
+# Run specific test file
+pytest tests/test_security.py -v
+
+# Run tests matching pattern
+pytest tests/ -k "test_validation" -v
+```
+
 ## Release Process
 
 This project uses manual releases via GitHub Releases. To create a new release:

pyproject.toml

@@ -13,4 +13,5 @@ dependencies = [
 dev = [
     "pytest>=7.0.0",
     "pytest-mock>=3.10.0",
+    "pytest-xdist>=3.0.0",
 ]