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Testing Serializers

Test custom serialization logic in isolation or via the mock provided by syntropylog/testing. The package does not export MockSerializerRegistry.

Testing serializer functions in isolation​

Serializers are functions that transform objects into strings. Unit test them directly:

// src/serializers.ts
export function serializeUser(user: any): string {
  return JSON.stringify({
    id: user.id,
    name: user.name,
    email: user.email,
    createdAt: user.createdAt?.toISOString?.(),
  });
}
// tests/serializers.test.ts
import { describe, it, expect } from 'vitest';
import { serializeUser } from '../src/serializers';

describe('Serializers', () => {
  it('should serialize user correctly', () => {
    const user = {
      id: 123,
      name: 'John Doe',
      email: 'john@example.com',
      createdAt: new Date('2023-01-01'),
    };
    const result = serializeUser(user);
    expect(result).toContain('"name":"John Doe"');
    expect(result).toContain('"email":"john@example.com"');
  });

  it('should handle null and undefined', () => {
    expect(serializeUser(null)).toBe('null');
  });
});

Using the mock’s serialization manager​

When testing code that uses syntropyLog.getSerializer() (or the serialization pipeline), use createSyntropyLogMock() so no real init is required. The mock exposes getSerializationManager() for stubbing if needed.

import { createTestHelper } from 'syntropylog/testing';

const testHelper = createTestHelper(vi.fn);

it('should log with serialized payload', async () => {
  const mock = testHelper.mockSyntropyLog;
  const logger = mock.getLogger('test');
  logger.info('User action', { userId: 1 });
  // Assert on behavior; serialization is internal to the mock
});