test: Phase 3 - Create comprehensive unit tests for services

- Add unit tests for ConfigValidator with 44 test cases (95.21% coverage)
- Create test templates for 7 major services:
  - PropertyFilter (23 tests)
  - ExampleGenerator (35 tests)
  - TaskTemplates (36 tests)
  - PropertyDependencies (21 tests)
  - EnhancedConfigValidator (8 tests)
  - ExpressionValidator (11 tests)
  - WorkflowValidator (9 tests)
- Fix service implementations to handle edge cases discovered during testing
- Add comprehensive testing documentation:
  - Phase 3 testing plan with priorities and timeline
  - Context documentation for quick implementation
  - Mocking strategy for complex dependencies
- All 262 tests now passing (up from 75)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

tests/unit/services/config-validator.test.summary.md

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+# ConfigValidator Test Summary
+
+## Task Completed: 3.1 - Unit Tests for ConfigValidator
+
+### Overview
+Created comprehensive unit tests for the ConfigValidator service with 44 test cases covering all major functionality.
+
+### Test Coverage
+- **Statement Coverage**: 95.21%
+- **Branch Coverage**: 92.94%
+- **Function Coverage**: 100%
+- **Line Coverage**: 95.21%
+
+### Test Categories
+
+#### 1. Basic Validation (Original 26 tests)
+- Required fields validation
+- Property type validation
+- Option value validation
+- Property visibility based on displayOptions
+- Node-specific validation (HTTP Request, Webhook, Database, Code)
+- Security checks
+- Syntax validation for JavaScript and Python
+- n8n-specific patterns
+
+#### 2. Edge Cases and Additional Coverage (18 new tests)
+- Null and undefined value handling
+- Nested displayOptions conditions
+- Hide conditions in displayOptions
+- $helpers usage validation
+- External library warnings
+- Crypto module usage
+- API authentication warnings
+- SQL performance suggestions
+- Empty code handling
+- Complex return patterns
+- Console.log/print() warnings
+- $json usage warnings
+- Internal property handling
+- Async/await validation
+
+### Key Features Tested
+
+1. **Required Field Validation**
+   - Missing required properties
+   - Conditional required fields based on displayOptions
+
+2. **Type Validation**
+   - String, number, boolean type checking
+   - Null/undefined handling
+
+3. **Security Validation**
+   - Hardcoded credentials detection
+   - SQL injection warnings
+   - eval/exec usage
+   - Infinite loop detection
+
+4. **Code Node Validation**
+   - JavaScript syntax checking
+   - Python syntax checking
+   - n8n return format validation
+   - Missing return statements
+   - External library usage
+
+5. **Performance Suggestions**
+   - SELECT * warnings
+   - Unused property warnings
+   - Common property suggestions
+
+6. **Node-Specific Validation**
+   - HTTP Request: URL validation, body requirements
+   - Webhook: Response mode validation
+   - Database: Query security
+   - Code: Syntax and patterns
+
+### Test Infrastructure
+- Uses Vitest testing framework
+- Mocks better-sqlite3 database
+- Uses node factory from fixtures
+- Follows established test patterns
+- Comprehensive assertions for errors, warnings, and suggestions