Integration E2E Testing

Integration Test & E2E Test Design/​Implementation Rules

Test Types and Limits

Critical User Journey: Features with revenue impact, legal requirements, or daily use by majority of users

Behavior-First Principle

Observability Check (All YES = Include)

Include/​Exclude Criteria

Include: Business logic accuracy, data integrity, user-visible features, error handling Exclude: External live connections, performance metrics, implementation details, UI layout

Skeleton Specification

Required Comment Format

// AC: "[Acceptance criteria original text]"
// ROI: [0-100] | Business Value: [0-10] | Frequency: [0-10]
// Behavior: [Trigger] -> [Process] -> [Observable Result]
// @category: core-functionality | integration | edge-case | ux | e2e
// @dependency: none | [component name] | full-system
// @complexity: low | medium | high
it.todo('[AC number]: [Test name]')

Property Annotations

// Property: `[Verification expression]`
// fast-check: fc.property(fc.[arbitrary], (input) => [invariant])
it.todo('[AC number]-property: [Invariant description]')

ROI Calculation

ROI = (Business Value x Frequency + Legal Requirement x 10 + Defect Detection) / Total Cost

Implementation Rules

Property-Based Test Implementation

When Property annotation exists, fast-check library is required:

import fc from 'fast-check'

it('AC2-property: Model name is always gemini-3-pro-image-preview', () => {
  fc.assert(
    fc.property(fc.string(), (prompt) => {
      const result = client.generate(prompt)
      return result.model === 'gemini-3-pro-image-preview'
    })
  )
})

Requirements:

• Write in fc.assert(fc.property(...)) format
• Reflect skeleton's // fast-check: comment directly in implementation
• When failure case discovered, add as concrete unit test (regression prevention)

Behavior Verification Implementation

Behavior Description Verification Levels:

Pass Criteria: Pass if "observable result" is verified as return value or mock call argument of test target

Verification Item Determination Rules

Integration Test Mock Boundaries

Judgment Flow:

1. External API (HTTP communication) -> Mock required
2. Component interaction under test -> Actual required
3. Log output verification needed -> Use verifiable mock (vi.fn())
4. Log output verification not needed -> Actual or ignore

E2E Test Execution Conditions

• Execute only after all components are implemented
• Do not use mocks (@dependency: full-system)

Review Criteria

Skeleton and Implementation Consistency

Implementation Quality