Test Runner

Expert skill for test execution and failure diagnosis.

Quick Start

Test Checklist:
- [ ] Environment configured
- [ ] Tests run or failures captured
- [ ] Failed tests diagnosed
- [ ] Coverage report generated

When to Use

• Running test suites
• Debugging failing tests
• Setting up CI/CD pipelines
• Analyzing test coverage
• Identifying flaky tests

Framework Commands

JavaScript

jest                    # Run all
jest path/to/test.ts    # Specific file
jest --coverage       # With coverage
jest --watch          # Watch mode

Python

pytest                  # Run all
pytest tests/test.py    # Specific file
pytest --cov=src        # With coverage
pytest -v              # Verbose

Rust

cargo test              # Run all
cargo test test_name    # Specific test
cargo test -- --nocapture  # Show output

Go

go test ./...           # Run all
go test -v ./...        # Verbose
go test -cover ./...    # With coverage

Bash

bats tests/             # Run all
bats tests/file.bats    # Specific file

Diagnosing Failures

Step 1: Identify Error Type

Step 2: Isolate Test

pytest test.py::test_func -v     # Python
jest --testNamePattern="test"     # Jest
cargo test test_name               # Rust

Step 3: Check Environment

pip list | grep pytest            # Python
npm list jest                      # Node
# ./scripts/setup-test-db.sh       # Test data (create if needed for project)

Coverage Analysis

Generate Reports

# Jest
jest --coverage --coverageReporters=text-summary

# Python
pytest --cov=src --cov-report=html

# Rust
cargo tarpaulin --out Html

# Go
go test -coverprofile=coverage.out ./...
go tool cover -html=coverage.out

Coverage Targets

Flaky Test Detection

# Run multiple times
for i in {1..10}; do pytest || echo "Failed run $i"; done

# Identify patterns:
# - Time-based (timeout issues)
# - State-dependent (order matters)
# - Async race conditions

Best Practices

DO:

• Run tests locally before commit
• Write edge case tests
• Mock external dependencies
• Keep tests fast (<100ms)
• Clean up test state
• Use descriptive names

DON'T:

• Skip tests without TODO
• Hardcode timeouts
• Test implementation details
• Share mutable state
• Ignore flaky tests
• Use sleep without reason

Quality Criteria

• Tests run or failures diagnosed
• Coverage meets targets
• No flaky tests
• Test environment documented
• CI/CD configured
• Clear error messages

See Also

• testing-strategy — Choose testing approaches and plan test suites (incl. its testdata appendix)
• nested-build-isolation — Isolate nested subprocess builds, tests, or coverage runners
• dogfood — Exploratory testing of web applications

Rationalizations

Red Flags

• Tests skipped without a tracked follow-up
• Coverage drops below minimum thresholds on new code
• Flaky tests re-run instead of root-caused

References

• agents-docs/SKILLS.md - Skill framework guide

Voice & Context

• Default: professional + blog
• Reference: voice-profiles skill for definitions and auto-detection.