create-mock-repository

Mock Repository Generator

Generates InMemory (Fake) repository implementations for testing.

Characteristics

• No database — stores entities in memory
• Fast — no I/O operations
• Isolated — fresh state per test
• Deterministic — predictable behavior
• Implements interface — same contract as real repository

Template

<?php

declare(strict_types=1);

namespace Tests\Fake;

use {RepositoryInterface};
use {Entity};
use {EntityId};

final class InMemory{Entity}Repository implements {RepositoryInterface}
{
    /** @var array<string, {Entity}> */
    private array $entities = [];

    public function save({Entity} $entity): void
    {
        $this->entities[$entity->id()->toString()] = $entity;
    }

    public function findById({EntityId} $id): ?{Entity}
    {
        return $this->entities[$id->toString()] ?? null;
    }

    public function delete({Entity} $entity): void
    {
        unset($this->entities[$entity->id()->toString()]);
    }

    /** @return list<{Entity}> */
    public function findAll(): array
    {
        return array_values($this->entities);
    }

    public function clear(): void
    {
        $this->entities = [];
    }
}

Generation Instructions

1. Read the repository interface:

   • Extract all method signatures
   • Identify entity type
   • Identify ID type

2. Generate InMemory implementation:

   • Array storage keyed by ID
   • Implement all interface methods
   • Add clear() for test cleanup

3. Handle complex queries:

   • Use array_filter for criteria
   • Support specifications if used
   • Implement pagination with array_slice

4. Add test helpers (optional):

   • getAll() — access internal state
   • has(Id $id) — check existence
   • count() — entity count

5. File placement:

   • tests/Fake/InMemory{Entity}Repository.php
   • Or tests/Double/ directory

Best Practices

1. Match interface exactly — same method signatures
2. Isolate per test — use clear() in tearDown
3. Avoid complexity — simple in-memory logic
4. Document deviations — if behavior differs from real impl
5. Consider thread safety — for parallel tests (usually not needed)

References

• references/examples.md — Complete repository examples (User, Order, Product)
• references/other-fakes.md — EventDispatcher, Mailer, Clock fakes