mock-updater

name	mock-updater
description	Orchestrate parallel subagents to update all mock implementations when a port interface changes
user_invocable	true

Parallel Mock Updater

When a port interface changes, this skill orchestrates parallel subagents to update every mock implementation across the test suite.

When to Use

• After adding, removing, or changing a method on a port interface
• After pnpm typecheck reveals mock type errors across multiple test files
• When the check-mock-completeness hook warns about incomplete mocks
• After running /serena-impact-analysis and seeing many test files in the blast radius

Steps

1. Identify the Interface Change

Determine what changed on the port interface:

# See the diff
git diff packages/core/src/application/ports/output/

Record:

• Interface name: e.g., IFeatureRepository
• Interface file: e.g., packages/core/src/application/ports/output/repositories/feature-repository.interface.ts
• Added methods: e.g., findByIds(ids: string[]): Promise<Feature[]>
• Removed methods: e.g., (none)
• Changed signatures: e.g., (none)

2. Check for Centralized Mock Factory

ls tests/helpers/mock-*.helper.ts

If a factory exists for this interface (e.g., tests/helpers/mock-feature-repository.helper.ts):

• Update the factory only — all consumers inherit the fix automatically
• Skip to Step 6 (Verify)

If no factory exists, check mock duplication count:

grep -rl "vi\.fn()" tests/ | xargs grep -l "IFeatureRepository" | wc -l

If count >= 5, strongly recommend creating a factory first with /mock-factory — it's a one-time investment that makes all future updates trivial.

3. Find All Affected Test Files

grep -rl "IFeatureRepository\|mockFeatureRepo\|featureRepository.*vi\.fn" tests/ | sort

Save this list. Group into batches of ~5 files per subagent.

4. Read the Current Interface

Read the full interface to know what methods each mock must implement:

cat packages/core/src/application/ports/output/repositories/feature-repository.interface.ts

5. Deploy Parallel Update Subagents

For each batch of test files, deploy a subagent using the Agent tool. Each subagent gets:

• The complete interface definition
• Its assigned list of files (max 5)
• The specific change (which methods to add/remove/modify)

Deployment pattern:

Agent(
  description: "Update mocks batch 1",
  name: "mock-update-1",
  prompt: "Update mock objects in these test files to match the current IFeatureRepository interface.

The interface now has these methods:
- create(feature: Feature): Promise<void>
- findById(id: string): Promise<Feature | null>
- findByIds(ids: string[]): Promise<Feature[]>  ← NEW
- list(): Promise<Feature[]>
- listActive(): Promise<Feature[]>
- update(feature: Feature): Promise<void>
- delete(id: string): Promise<void>

Files to update:
1. /Users/.../tests/unit/application/use-cases/create-feature.test.ts
2. /Users/.../tests/unit/application/use-cases/list-features.test.ts
3. /Users/.../tests/unit/application/use-cases/delete-feature.test.ts

For each file:
- Find the mock object (usually in beforeEach or at describe scope)
- Add: findByIds: vi.fn().mockResolvedValue([])
- Do NOT change existing mock return values or test assertions
- Only add the missing method with a sensible default"
)

Deploy all batches in a single message with multiple Agent tool calls for true parallelism:

// In a single response, call Agent multiple times:
Agent(name: "mock-update-1", prompt: "Update files 1-5...")
Agent(name: "mock-update-2", prompt: "Update files 6-10...")
Agent(name: "mock-update-3", prompt: "Update files 11-15...")

6. Verify

After all subagents complete:

# Type check — all mocks must satisfy the interface
pnpm typecheck

# Run unit tests — no regressions
pnpm test:unit

# Double-check no files were missed
grep -rl "IFeatureRepository" tests/ | xargs grep -L "findByIds" 2>/dev/null

7. Consider Creating a Factory

If you just updated 10+ files individually, create a centralized factory to prevent this pain next time:

/mock-factory

Then refactor all test files to use it. Future interface changes will only require updating one file.

Decision Tree

Interface changed
├── Factory exists? → Update factory only → Verify → Done
├── < 5 mocks? → Update manually → Verify → Done
└── >= 5 mocks?
    ├── Create factory first (/mock-factory) → Update factory → Refactor tests → Verify → Done
    └── Urgent? Deploy parallel subagents → Verify → Create factory later

Batching Guidelines

Mock count	Strategy
1-4	Update manually (no subagents needed)
5-15	2-3 subagents, ~5 files each
16-30	4-6 subagents, ~5 files each
30+	Create factory FIRST, then single factory update