TypeScript Test Skill

Generate unit tests by analyzing the source file's functions, branches, and logic flow.

Commands

Command	Description
/test-ts create <path>	Create tests for a file, folder, or module
/test-ts update <path>	Update existing tests

<path> can be:

• A file: utils.ts or #File
• A folder: src/lib/ or #Folder
• A module name: auth, user-service

Tip: Use Kiro's #File or #Folder context to quickly reference paths.

Workflow

Step 1: Analyze Source File

Read the source file and identify:

• All exported functions/classes/hooks
• All code branches (if/else, ternary, switch, try/catch)
• All async operations (Promise, async/await)
• All dependencies that need mocking
• All possible error paths

Step 2: Create Test Plan

For each function/method found:

1. List all execution paths
2. Identify inputs that trigger each path
3. Determine expected outputs for each path
4. Note edge cases (null, undefined, empty, boundary)

Step 3: Generate Tests

Create tests that cover every path identified in Step 2.

Coverage Target: 80%+

Every test file must cover:

• All exported functions
• All if/else branches
• All switch cases
• All try/catch blocks
• All async success/error paths

Consistent Pattern

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

describe('[FileName]', () => {
  beforeEach(() => {
    vi.clearAllMocks()
  })

  describe('[functionName]', () => {
    // Test each execution path found in the function
    it('should [expected behavior] when [condition]', () => {
      // Arrange - setup
      // Act - call function
      // Assert - verify result
    })
  })
})

Naming Convention

• Test file: [source-file].test.ts or [source-file].spec.ts
• Describe block: Match source file/class name
• Test case: should [action] when [condition]

Mocking

Mock all external dependencies:

vi.mock('[dependency-path]', () => ({
  [exportName]: vi.fn(),
}))

Running Tests

pnpm test              # Run all
pnpm test:coverage     # With coverage report