hackathon/docs/testing/test-strategy.md

Test Strategy - Log Data Collector

Overview

This document defines the comprehensive testing strategy for the Log Data Collector system, ensuring full validation of functional, non-functional, architectural, and normative requirements.

Test Framework Stack

Core Testing Tools

• JUnit 5 (Jupiter) - Unit and integration testing framework (Req-Test-3)
• Mockito 5.x - Mocking framework for dependencies (Req-Test-3)
• Maven Surefire - Unit test execution (Req-Test-4)
• Maven Failsafe - Integration test execution (Req-Test-4)

Mock Servers

• WireMock - Mock HTTP server for endpoint simulation (Req-Test-1)
• gRPC Testing - In-process gRPC server for transmission testing (Req-Test-2)

Additional Tools

• AssertJ - Fluent assertions for better readability
• Awaitility - Asynchronous test support
• JMH - Java Microbenchmark Harness for performance testing

Test Pyramid Structure

                 /\
                /E2E\          5% - End-to-End (Full system)
               /------\
              /Integr. \       20% - Integration (Component interaction)
             /----------\
            /   Unit     \     75% - Unit (Individual components)
           /--------------\

Test Categories

1. Unit Tests (75% of test suite)

Scope: Individual components in isolation with mocked dependencies

Coverage Target: 90% line coverage, 85% branch coverage

Test Classes:

• ConfigurationLoaderTest - Configuration parsing and validation
• DataSerializerTest - JSON/Protocol Buffer serialization
• CircularBufferTest - Buffer operations and thread safety
• RetryMechanismTest - Retry logic and backoff strategies
• HealthCheckEndpointTest - Health check HTTP/gRPC responses
• HttpCollectorTest - HTTP endpoint collection logic
• GrpcTransmitterTest - gRPC transmission logic
• StartupSequenceTest - Application startup orchestration

Characteristics:

• Fast execution (< 100ms per test)
• No external dependencies
• Deterministic results
• Isolated failures

2. Integration Tests (20% of test suite)

Scope: Component interactions with real infrastructure (mocked external systems)

Coverage Target: Key integration paths and data flows

Test Classes:

• HttpCollectionIntegrationTest - HTTP collection with WireMock server
• GrpcTransmissionIntegrationTest - gRPC transmission with test server
• EndToEndDataFlowTest - Complete IF1 → IF2 data pipeline
• ConfigurationFileIntegrationTest - Real YAML file loading
• CircularBufferIntegrationTest - Multi-threaded buffer operations

Characteristics:

• Moderate execution time (< 5s per test)
• Real component interaction
• Mock external systems only
• Controlled test environment

3. End-to-End Tests (5% of test suite)

Scope: Full system validation with all components running

Coverage Target: Critical user scenarios and requirement validation

Test Scenarios:

• E2EStartupAndCollectionTest - Complete startup and first collection
• E2EFailureRecoveryTest - System resilience under failures
• E2EPerformanceTest - Load testing with 1000 endpoints
• E2EConfigurationReloadTest - Runtime configuration updates

Characteristics:

• Longer execution (< 30s per test)
• Real system deployment
• End-user perspective
• High-level validation

4. Performance Tests

Scope: Non-functional requirement validation

Test Classes:

• PerformanceConcurrentEndpointsTest - 1000 concurrent endpoints (Req-NFR-1)
• PerformanceMemoryUsageTest - Memory consumption < 4096MB (Req-NFR-2)
• PerformanceVirtualThreadTest - Virtual thread efficiency (Req-Arch-6)
• PerformanceStartupTimeTest - Startup time measurements

Execution: Separate Maven profile (performance) for CI/CD integration

5. Reliability Tests

Scope: Failure scenarios and recovery mechanisms

Test Classes:

• ReliabilityStartupSequenceTest - Startup component ordering (Req-FR-1 to Req-FR-8)
• ReliabilityGrpcRetryTest - gRPC connection failures (Req-FR-6, Req-FR-30)
• ReliabilityHttpFailureTest - HTTP endpoint failures (Req-FR-20)
• ReliabilityBufferOverflowTest - Buffer overflow handling (Req-FR-27)
• ReliabilityPartialFailureTest - Subset endpoint failures

Execution: Part of regular test suite with failure injection

6. Compliance Tests

Scope: Normative requirement validation

Test Classes:

• ComplianceErrorDetectionTest - Error detection mechanisms (Req-Norm-3)
• ComplianceIso9001Test - ISO-9001 quality measures (Req-Norm-1)
• ComplianceEn50716Test - EN 50716 software measures (Req-Norm-2)
• ComplianceAuditLoggingTest - Audit trail verification

Execution: Automated compliance report generation

Test Data Management

Test Configuration Files

• src/test/resources/test-config.yaml - Valid test configuration
• src/test/resources/test-config-invalid.yaml - Invalid format testing
• src/test/resources/test-config-minimal.yaml - Minimal valid config
• src/test/resources/test-config-maximal.yaml - Maximum complexity config

Test Data Generators

• TestDataFactory - Create test log entries
• TestConfigurationBuilder - Fluent configuration creation
• TestEndpointBuilder - HTTP/gRPC endpoint creation

Mock Server Definitions

• HttpMockServerSetup - WireMock server configuration
• GrpcMockServerSetup - gRPC test server configuration

Test Execution Strategy

Local Development

# Run all unit tests
mvn test

# Run integration tests
mvn verify -P integration-tests

# Run performance tests
mvn verify -P performance-tests

# Run all tests with coverage
mvn verify -P all-tests jacoco:report

CI/CD Pipeline

1. Commit Stage: Unit tests (fast feedback)
2. Integration Stage: Integration tests + unit tests
3. Performance Stage: Performance tests (nightly)
4. Compliance Stage: Compliance validation + audit report

Test Execution Order

1. Unit tests (parallel execution)
2. Integration tests (sequential by category)
3. E2E tests (sequential)
4. Performance tests (isolated environment)

Assertion Strategy

Unit Tests

// Use AssertJ for fluent assertions
assertThat(config.getEndpoints())
    .isNotEmpty()
    .hasSize(3)
    .allMatch(e -> e.getUrl() != null);

// Verify mock interactions
verify(grpcClient, times(1)).sendLogData(any());
verifyNoMoreInteractions(grpcClient);

Integration Tests

// Await asynchronous results
await().atMost(5, SECONDS)
    .untilAsserted(() ->
        assertThat(buffer.size()).isGreaterThan(0));

// Verify WireMock interactions
wireMock.verify(exactly(1),
    getRequestedFor(urlEqualTo("/health")));

Performance Tests

// JMH benchmark assertions
assertThat(result.getScore())
    .isLessThan(1000); // ops/ms threshold

// Memory assertions
assertThat(memoryUsed)
    .isLessThan(4096 * 1024 * 1024L); // 4096 MB

Coverage Requirements

Minimum Coverage Thresholds

• Line Coverage: 85% overall, 90% for critical components
• Branch Coverage: 80% overall, 85% for decision logic
• Method Coverage: 90% overall

Excluded from Coverage

• Generated code (Protocol Buffers, builders)
• Main entry points (public static void main)
• Exception constructors
• Trivial getters/setters

Coverage Tools

• JaCoCo - Code coverage measurement
• SonarQube - Coverage analysis and technical debt tracking

Test Naming Convention

Unit Tests

should{ExpectedBehavior}_when{Condition}_given{State}

Examples:
- shouldReturnConfiguration_whenFileExists_givenValidYaml()
- shouldThrowException_whenFileNotFound_givenInvalidPath()

Integration Tests

should{IntegrateComponents}_when{Scenario}_given{Setup}

Examples:
- shouldCollectData_whenHttpEndpointResponds_givenMockServer()
- shouldRetryTransmission_whenGrpcFails_givenRetryPolicy()

Performance Tests

should{MeetRequirement}_when{LoadCondition}_given{SystemState}

Examples:
- shouldHandleConcurrentEndpoints_whenLoading1000Endpoints_givenVirtualThreads()
- shouldStayWithinMemoryLimit_whenBufferFull_givenMaxCapacity()

Mock Strategy

What to Mock

• External HTTP endpoints (WireMock)
• gRPC server connections (in-process test server)
• File system operations (optional, prefer test files)
• Time-dependent operations (Clock abstraction)

What NOT to Mock

• Domain objects (value objects, entities)
• In-memory data structures (test real implementation)
• Simple utilities (no behavior to mock)
• Configuration objects (use test builders)

Mockito Patterns

// Stub return values
when(configLoader.load(anyString()))
    .thenReturn(testConfiguration);

// Verify interactions
verify(transmitter).send(argThat(data ->
    data.getTimestamp().isAfter(testStart)));

// Spy on real objects
ConfigurationLoader spy = spy(realConfigLoader);
doReturn(testConfig).when(spy).loadFromFile(any());

Test Environment Setup

Test Resources

src/test/
├── java/
│   └── com/logcollector/
│       ├── unit/           # Unit tests
│       ├── integration/    # Integration tests
│       ├── e2e/           # End-to-end tests
│       ├── performance/   # Performance tests
│       └── util/          # Test utilities
└── resources/
    ├── test-config.yaml
    ├── logback-test.xml   # Test logging config
    └── mockito-extensions/

Test Fixtures

• @BeforeEach - Test-specific setup
• @BeforeAll - Class-level setup (expensive resources)
• @AfterEach - Test cleanup
• @AfterAll - Class-level cleanup

Test Isolation

• Each test creates its own data
• No shared mutable state between tests
• Independent test execution order
• Parallel test execution where possible

Continuous Testing

Pre-Commit Hooks

• Run unit tests locally
• Verify code style (Checkstyle)
• Static analysis (SpotBugs)

CI/CD Integration

• Automated test execution on every commit
• Coverage trend tracking
• Performance regression detection
• Test failure notifications

Test Reporting

• JUnit XML reports for CI tools
• HTML coverage reports (JaCoCo)
• Test execution time tracking
• Flaky test detection

Requirement Traceability

Every test class includes Javadoc with requirement mapping:

/**
 * Tests for ConfigurationLoader component.
 *
 * @validates Req-FR-11 - Configuration file detection
 * @validates Req-FR-12 - Configuration parsing
 * @validates Req-FR-13 - Configuration validation
 * @validates Req-Norm-3 - Error detection
 */
@DisplayName("Configuration Loader Tests")
class ConfigurationLoaderTest {
    // Test methods...
}

See test-requirement-mapping.md for complete test-to-requirement matrix.

Test Maintenance

Test Review Criteria

• ✓ Clear test naming
• ✓ Single assertion focus
• ✓ Requirement traceability
• ✓ Fast execution (< 100ms for unit)
• ✓ Deterministic results
• ✓ Meaningful failure messages

Test Refactoring

• Extract common setup to test utilities
• Use test builders for complex objects
• Parameterize similar test scenarios
• Remove duplicate assertions

Test Debt Management

• Track flaky tests
• Identify slow tests
• Monitor coverage trends
• Refactor brittle tests

Success Metrics

Test Quality Metrics

• Test Coverage: > 85% line coverage
• Test Execution Time: < 5 minutes for full suite
• Test Stability: < 1% flaky test rate
• Bug Escape Rate: < 5% defects found in production

Test Effectiveness Metrics

• Defect Detection Rate: Tests catch 95%+ of bugs before production
• Requirement Coverage: 100% of requirements validated by tests
• Regression Prevention: Zero regression bugs in covered areas

References

• JUnit 5 User Guide: https://junit.org/junit5/docs/current/user-guide/
• Mockito Documentation: https://javadoc.io/doc/org.mockito/mockito-core
• WireMock Documentation: https://wiremock.org/docs/
• gRPC Testing Guide: https://grpc.io/docs/languages/java/basics/#testing
• JaCoCo Documentation: https://www.jacoco.org/jacoco/trunk/doc/

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Version: 1.0 Last Updated: 2025-11-19 Author: Test Strategist Agent Approval: Pending Architecture Review