test-fixing

name	test-fixing
description	Fix failing tests, prevent regressions when modifying logic, and maintain test coverage. Cooper uses Vitest for unit tests and Playwright for E2E tests.

Test Fixing

Purpose

Fix failing tests, prevent regressions when modifying logic, and maintain test coverage. Cooper uses Vitest for unit/component tests and Playwright for E2E tests.

When to Use

• Any test fails after your changes
• Modifying logic that has existing tests
• Adding new features that need test coverage

When NOT to Use

• Tests unrelated to your changes (document and move on)
• Flaky tests that fail intermittently (report, don't fix inline)

Activation Rules

Step 1: Establish Baseline

Before making changes, run the relevant test suite:

# Unit/component tests
npm test

# Specific test file
npx vitest run tests/components/MyComponent.test.tsx

# E2E tests (requires build first)
npm run test:e2e

Step 2: Run Tests After Changes

After every significant modification:

• Run npm test for unit/component tests
• If UI changed, run npm run test:e2e for E2E

Step 3: Fix Root Cause

Fix the code, not the test — unless the test itself is wrong.

• If test expectation is outdated → update the test
• If code broke the contract → fix the code
• If new behavior needs testing → add a new test

Step 4: Add Tests for New Features

Test file conventions:

• Unit tests: tests/components/<Component>.test.tsx
• Integration tests: tests/integration/<feature>.test.ts
• E2E tests: tests/e2e/<flow>.spec.ts

Test patterns:

import { describe, it, expect, vi } from 'vitest';

describe('ComponentName', () => {
  it('should handle expected behavior', () => {
    // Arrange → Act → Assert
  });
});

Cooper-Specific Notes

• Vitest for unit/component tests (vitest.config.ts)
• Playwright for E2E tests (playwright.config.ts)
• Mock IPC calls with vi.fn() for renderer component tests
• Test files live in tests/ directory (not co-located)

Success Criteria

• All tests pass after changes (npm test exits 0)
• New features have at least one test
• No test was deleted to make the suite pass

Related Skills

• review-implementing — For validating changes