TDD Guide
It generates tests, analyzes coverage, and guides red-green-refactor workflows.
Install
npx promptshop add tdd-guideDetails
What This Skill Does
The TDD Guide assists developers in adopting test-driven development practices across various frameworks. It generates tests, analyzes coverage, and guides red-green-refactor workflows. This skill is useful for improving code quality and ensuring comprehensive test coverage.
When to Use
Generate tests from existing codeAnalyze coverage gaps in test suitesImplement a new feature using TDDValidate code changes with automated testsRefactor code while maintaining test coverageEnsure code meets coverage thresholds
Key Features
Generates test stubs for Jest, Pytest, JUnit, VitestAnalyzes coverage reports (LCOV/JSON/XML)Prioritizes coverage gapsGuides red-green-refactor workflowValidates tests compile and cover happy/error pathsSupports TypeScript, JavaScript, Python, Java
Manual Installation
Manual installation
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
| Tool | Purpose | Usage |
|---|---|---|
| test_generator.py | Generate test cases from code/requirements | python scripts/test_generator.py --input source.py --framework pytest |
| coverage_analyzer.py | Parse and analyze coverage reports | python scripts/coverage_analyzer.py --report lcov.info --threshold 80 |
| tdd_workflow.py | Guide red-green-refactor cycles | python scripts/tdd_workflow.py --phase red --test test_auth.py |
| fixture_generator.py | Generate test data and mocks | python 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
| Scope | Details |
|---|---|
| Unit test focus | Integration and E2E tests require different patterns |
| Static analysis | Cannot execute tests or measure runtime behavior |
| Language support | Best for TypeScript, JavaScript, Python, Java |
| Report formats | LCOV, JSON, XML only; other formats need conversion |
| Generated tests | Provide 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 SuiteTDD 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