Introduce selective mocking utilities for tests

[ewilderj]

Description

Create reusable mocking utilities to reduce code duplication in tests and improve test maintainability across the codebase.

Work Required

1. Create Mock Page Utility: Add test/utils/mockPage.js for Playwright page mocking
2. Create HTTP Mock Utility: Add test/utils/httpMocks.js for external API mocking
3. Refactor Existing Tests: Update existing tests to use new utilities
4. Document Usage: Add documentation for utility usage patterns

Implementation Details

Based on existing test patterns and upcoming test needs:

test/utils/mockPage.js

• Mock Playwright page object for capture system tests
• Provide common page methods: evaluate(), waitForTimeout(), screenshot()
• Mock page properties and events for visual detector tests
• Support method chaining and Promise-based APIs

test/utils/httpMocks.js

• Mock axios/fetch for external API calls in stocks/weather modules
• Provide utilities for mocking HTTP responses, timeouts, errors
• Support rate limiting simulation for API testing
• Include common response patterns for external services

Current Test Patterns to Improve

From existing tests:

• test/templates.validation.api.test.js - Uses supertest for API testing
• Future capture system tests will need page mocking
• Future stocks/weather tests will need HTTP mocking

Mock Patterns Needed

Page Mocking

const mockPage = createMockPage({
  evaluate: jest.fn(),
  waitForTimeout: jest.fn(),
  screenshot: jest.fn()
});

HTTP Mocking

const httpMock = createHttpMock()
  .get('/api/external')
  .reply(200, { data: 'test' });

Files to Create

• test/utils/mockPage.js - Playwright page mocking utility
• test/utils/httpMocks.js - HTTP request mocking utility
• test/utils/index.js - Barrel export for utilities

Usage Guidelines

• Keep utilities focused and composable
• Provide clear documentation and examples
• Follow Jest mocking best practices
• Make utilities easy to extend for specific use cases

Acceptance Criteria

• Duplicate mock code is reduced across test files
• New utilities are adopted in new tests
• Existing tests can be refactored to use utilities where appropriate
• Utilities are well-documented with usage examples
• Mock utilities support common testing patterns in the codebase