Component Breakdown and Step-by-Step Implementation

🚧 Component 1: Repository Access and Setup

Goal: Clone private repositories and set up environment.

Steps:

1. Authenticate to Repository:

   • Setup SSH keys or personal access tokens (PATs) securely.
   • Tools: JGit (Java), Git CLI.

2. Clone Repository:

   • Implement clone logic using JGit.
   • Save to local temp directories.

3. Detect Build System:

   • Identify if it's Maven (pom.xml) or Gradle (build.gradle).

Outcome: You have a secure mechanism to clone and prepare repositories for analysis.

📊 Component 2: Coverage Measurement & Analysis

Goal: Measure initial coverage and identify coverage gaps.

Steps:

1. Integrate Coverage Tool (JaCoCo):

   • Automatically add JaCoCo plugin to Maven/Gradle build if not present.
   • Run mvn clean test or ./gradlew test with JaCoCo enabled.

2. Parse Coverage Reports:

   • Generate XML/HTML report.
   • Parse XML using Java (XPath/XML parsers) to identify classes/methods with low coverage (<90%).

Outcome: A list of target classes/methods needing tests.

🔍 Component 3: Test Generation Engine (LLM-based)

Goal: Generate meaningful Java unit tests automatically.

Steps:

1. Codebase Inspection:

   • Detect existing test libraries from the codebase (pom.xml or build.gradle).
   • Common: JUnit 5, Mockito.

2. LLM Integration:

   • Set up API integration (e.g., GPT-4 or local LLM).
   • Create a Java HTTP client to interact with the LLM API.

3. Prompt Engineering:

   • Design a prompt template to ask the LLM for targeted unit tests.
   • Example prompt:

     "Write a JUnit 5 unit test using Mockito for the following Java method. Cover all branches and handle edge cases clearly:"
     

4. Process and Validate LLM Output:

   • Verify code syntax (basic checks).
   • Save tests as .java files under standard test directory.

Outcome: Auto-generated, well-structured Java test files.

🛠 Component 4: Integration and Build Verification

Goal: Integrate new tests, build project, and ensure all tests pass.

Steps:

1. Integrate Tests into Project Structure:

   • Mirror original package structure under src/test/java.

2. Compile and Run Tests:

   • Run mvn test or ./gradlew test.
   • Catch and handle compilation errors or test failures.

3. Automated Result Handling:

   • Keep only tests that compile and pass.
   • Log failures for refinement in next iteration.

Outcome: Stable test suite incrementally increasing coverage.

🔄 Component 5: Self-Iteration Loop

Goal: Automatically repeat test generation until desired coverage (90%) is achieved.

Steps:

1. Iteration Controller:

   • Loop logic: While (coverage < 90%) { generateTests(); integrateTests(); measureCoverage(); }
   • Add logic to terminate after a defined max iteration count or minimal coverage gain threshold.

2. Feedback Mechanism:

   • After each iteration, pass uncovered lines/methods explicitly into the next LLM prompt for refined generation.

3. Persistent Progress:

   • Regularly commit incremental improvements locally.

Outcome: Automated and measurable progress toward target coverage.

📤 Component 6: Pull Request Automation

Goal: Automatically push improvements and create PRs for review.

Steps:

1. Automate Git Operations:

   • Use JGit to commit changes locally, push a new branch (e.g., test-coverage-improvement).

2. Pull Request Automation:

   • Integrate with Git hosting platform API (GitHub, GitLab, Bitbucket API) to create PRs automatically.
   • Include coverage statistics and test summary in PR description.

Outcome: Automated, review-ready PRs containing the generated tests.

📈 Component 7: Quality Evaluation (Optional)

Goal: Verify the quality and effectiveness of tests.

Steps:

1. Mutation Testing:

   • Integrate PITest to measure test suite robustness.
   • Generate mutation report indicating tests' effectiveness.

2. Test Quality Checks:

   • Optionally run static analysis for tests (SpotBugs/PMD).
   • Detect common test smells or poor assertions.

Outcome: A metric-driven validation ensuring high-quality test suites.

📡 Monitoring and Logging (Cross-Cutting Concern)

• Implement structured logging with SLF4J/Logback.
• Each component should produce clear logs about the actions performed, making it easy to debug.

Suggested Development Roadmap:

1. Phase 1:

   • Component 1 (Repo Access)
   • Component 2 (Coverage Analysis)

2. Phase 2:

   • Component 3 (LLM Test Generation)
   • Component 4 (Test Integration & Validation)

3. Phase 3:

   • Component 5 (Iteration Loop)
   • Component 6 (Automated PR creation)

4. Phase 4 (Optional but recommended):

   • Component 7 (Quality Evaluation)

Technical Stack Recommendation:

• Java: Primary language for automation tool (Spring Boot optional, but plain Java is sufficient)
• JGit: Git operations
• JaCoCo: Coverage measurement
• JUnit 5, Mockito: Standard testing frameworks (detected dynamically)
• GPT-4 (OpenAI API) or a local LLM like Mistral: Test generation
• Maven/Gradle: Project builds
• GitHub API / GitLab API: Automated PR management
• PITest: Mutation testing for quality assurance
• Docker (optional): Containerize the automation tool for deployment

Action Items to Start:

Immediate First Steps:

1. Set up a simple Java project with JGit and successfully clone a repository.
2. Integrate JaCoCo to measure and parse coverage report.
3. Set up an API client in Java to interact with an LLM service.
4. Experiment with prompt engineering to reliably generate unit tests from LLM responses.

This step-by-step approach breaks down complexity, allows incremental progress, and makes each component independently verifiable before integration.