Add testing documentation to README

README.md

@@ -230,8 +230,64 @@ go run cmd/server/main.go
 # Build
 go build -o server cmd/server/main.go
 
-# Test
+# Run all tests
 go test ./...
+
+# Run tests with verbose output
+go test ./... -v
+
+# Run specific test package
+go test ./internal/handlers -v
+go test ./internal/database -v
+go test ./tests/integration -v
+
+# Run with coverage
+go test ./... -cover
+```
+
+## Testing
+
+The project includes comprehensive tests:
+
+### Unit Tests
+- **config**: Configuration loading and validation (11 tests)
+- **database**: Database operations and models (9 tests)
+- **handlers**: Handler logic, custom filters, and validation (36 tests)
+
+### Integration Tests
+Full end-to-end tests using:
+- **Mock Technitium Server**: Simulates DNS API without external dependencies
+- **SQLite**: In-memory/temp database for isolated testing
+- **Gin Test Server**: HTTP testing without network
+
+Integration tests cover:
+- Space claiming workflow
+- Subdomain availability checking
+- Profanity filtering
+- Custom DWS/Tanishq Dubey trademark filtering
+- DynDNS2 protocol updates
+- Full end-to-end workflows
+
+### Test Files
+```
+internal/config/config_test.go          # Config tests
+internal/database/db_test.go            # Database tests
+internal/handlers/handlers_test.go      # Handler unit tests
+internal/handlers/validation.go         # Custom validators
+internal/testutil/mock_technitium.go    # Mock DNS server
+tests/integration/integration_test.go   # Integration tests
+```
+
+### Running Integration Tests
+```bash
+# Run all integration tests
+go test ./tests/integration -v
+
+# Run specific integration test
+go test ./tests/integration -v -run TestIntegration_FullWorkflow
+
+# Run with timeout
+go test ./tests/integration -v -timeout 30s
 ```
 
 ## License