test-gen

Test Generation

Automatically generate tests for code changes made during a story.

Detection

Analyze files created/modified by the implementer:

File Type	Test Type	Pattern
src/lib/*.ts	Unit test	src/lib/*.test.ts
src/app/api/**/*.ts	Integration test	src/app/api/**/*.test.ts
src/components/*.tsx	Component test	src/components/*.test.tsx
src/middleware.ts	Middleware test	src/middleware.test.ts
src/utils/*.ts	Unit test	src/utils/*.test.ts

Test Framework Detection

Read from DNA:

Framework	Import	Runner
Vitest	import { describe, it, expect } from 'vitest'	vitest run
Jest	import { describe, it, expect } from '@jest/globals'	jest
Mocha + Chai	import { expect } from 'chai'	mocha

If no test framework detected, recommend Vitest and generate setup.

Generation Rules

1. Follow existing test patterns in the codebase
2. One test file per source file (colocated)
3. Describe blocks mirror the function/component structure
4. Test the happy path first, then edge cases
5. Mock external dependencies (database, APIs)
6. Use factories for test data (not inline objects)

Integration

Called between IMPLEMENT and SELF-HEAL:

Phase 3: IMPLEMENT (agent writes code)
Phase 3.5: TEST GEN (auto-generate tests)
Phase 4: SELF-HEAL (run tests — including generated ones)

Coverage Tracking

After tests run, capture coverage delta:

Coverage before story: 72%
Coverage after story: 76%
Delta: +4%

Save to token-ledger alongside cost data.

Test Templates

Unit Test

import { describe, it, expect } from "vitest"
import { functionName } from "../src/module"

describe("functionName", () => {
  it("should handle the happy path", () => {
    const result = functionName(validInput)
    expect(result).toEqual(expectedOutput)
  })

  it("should handle edge cases", () => {
    expect(() => functionName(null)).toThrow()
    expect(functionName("")).toEqual(defaultValue)
  })
})

API Integration Test

import { describe, it, expect } from "vitest"

describe("POST /api/resource", () => {
  it("should create a resource", async () => {
    const res = await fetch("/api/resource", {
      method: "POST",
      body: JSON.stringify({ name: "test" }),
    })
    expect(res.status).toBe(201)
  })

  it("should reject invalid input", async () => {
    const res = await fetch("/api/resource", {
      method: "POST",
      body: JSON.stringify({}),
    })
    expect(res.status).toBe(400)
  })
})

Output Contract

output_contract:
  file_pattern: "**/*.test.{ts,tsx,js,jsx}"
  required_content:
    - "describe("
    - "it(" or "test("
    - "expect("
  min_tests_per_file: 2