# tdd-guide

TDD Guide Test-driven development skill for generating tests, analyzing coverage, and guiding red-green-refactor workflows across Jest, Pytest, JUnit, and Vitest. Workflows Generate Tests from Code Provide source code (TypeScript, JavaScript, Python, Java) Specify target framework (Jest, Pytest, JUnit, Vitest) Run test_generator.py with requirements Review generated test stubs

Validation: Tests compile and cover happy path, error cases, edge cases

Analyze Coverage Gaps

Generate coverage report from test runner (npm test -- --coverage)

Run coverage_analyzer.py on LCOV/JSON/XML report Review prioritized gaps (P0/P1/P2) Generate missing tests for uncovered paths

Validation: Coverage meets target threshold (typically 80%+)

TDD New Feature Write failing test first (RED) Run tdd_workflow.py --phase red to validate Implement minimal code to pass (GREEN) Run tdd_workflow.py --phase green to validate Refactor while keeping tests green (REFACTOR)

Validation: All tests pass after each cycle

Examples Test Generation — Input → Output (Pytest) Input source function (math_utils.py): def divide(a: float, b: float) -> float: if b == 0: raise ValueError("Cannot divide by zero") return a / b

Command:

python scripts/test_generator.py --input math_utils.py --framework pytest Generated test output (test_math_utils.py): import pytest from math_utils import divide class TestDivide: def test_divide_positive_numbers(self): assert divide(10, 2) == 5.0 def test_divide_negative_numerator(self): assert divide(-10, 2) == -5.0 def test_divide_float_result(self): assert divide(1, 3) == pytest.approx(0.333, rel=1e-3) def test_divide_by_zero_raises_value_error(self): with pytest.raises(ValueError, match="Cannot divide by zero"): divide(10, 0) def test_divide_zero_numerator(self): assert divide(0, 5) == 0.0 Coverage Analysis — Sample P0/P1/P2 Output

Command:

python scripts/coverage_analyzer.py --report lcov.info --threshold 80 Sample output: Coverage Report — Overall: 63% (threshold: 80%) P0 — Critical gaps (uncovered error paths): auth/login.py:42-58 handle_expired_token() 0% covered payments/process.py:91-110 handle_payment_failure() 0% covered P1 — High-value gaps (core logic branches): users/service.py:77 update_profile() — else branch 0% covered orders/cart.py:134 apply_discount() — zero-qty guard 0% covered P2 — Low-risk gaps (utility / helper functions): utils/formatting.py:12 format_currency() 0% covered

Recommended: Generate tests for P0 items first to reach 80% threshold.

Key Tools ToolPurposeUsagetest_generator.pyGenerate test cases from code/requirementspython scripts/test_generator.py --input source.py --framework pytestcoverage_analyzer.pyParse and analyze coverage reportspython scripts/coverage_analyzer.py --report lcov.info --threshold 80tdd_workflow.pyGuide red-green-refactor cyclespython scripts/tdd_workflow.py --phase red --test test_auth.pyfixture_generator.pyGenerate test data and mockspython scripts/fixture_generator.py --entity User --count 5 Additional scripts: framework_adapter.py (convert between frameworks), metrics_calculator.py (quality metrics), format_detector.py (detect language/framework), output_formatter.py (CLI/desktop/CI output). Input Requirements For Test Generation: Source code (file path or pasted content) Target framework (Jest, Pytest, JUnit, Vitest) Coverage scope (unit, integration, edge cases) For Coverage Analysis: Coverage report file (LCOV, JSON, or XML format)

Optional: Source code for context
Optional: Target threshold percentage

For TDD Workflow: Feature requirements or user story Current phase (RED, GREEN, REFACTOR) Test code and implementation status Limitations ScopeDetailsUnit test focusIntegration and E2E tests require different patternsStatic analysisCannot execute tests or measure runtime behaviorLanguage supportBest for TypeScript, JavaScript, Python, JavaReport formatsLCOV, JSON, XML only; other formats need conversionGenerated testsProvide scaffolding; require human review for complex logic When to use other tools: E2E testing: Playwright, Cypress, Selenium Performance testing: k6, JMeter, Locust Security testing: OWASP ZAP, Burp Suite