Test Coverage Improver #84
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| --- | |
| name: Test Coverage Improver | |
| description: Daily analyzer that finds complex, under-tested functions and generates comprehensive tests | |
| on: | |
| schedule: daily | |
| workflow_dispatch: | |
| permissions: | |
| contents: read | |
| issues: read | |
| pull-requests: read | |
| engine: copilot | |
| network: | |
| allowed: | |
| - defaults | |
| - containers | |
| steps: | |
| - name: Checkout full repository | |
| uses: actions/checkout@v6 | |
| with: | |
| fetch-depth: 1 | |
| persist-credentials: false | |
| - name: Set up Go | |
| uses: actions/setup-go@v6 | |
| with: | |
| go-version-file: go.mod | |
| cache: true | |
| safe-outputs: | |
| create-pull-request: | |
| title-prefix: "[test] " | |
| labels: [testing, automation] | |
| draft: true | |
| tools: | |
| serena: ["go"] | |
| cache-memory: true | |
| github: | |
| toolsets: [default] | |
| allowed-repos: ["github/gh-aw-mcpg"] | |
| min-integrity: unapproved | |
| edit: | |
| bash: ["*"] | |
| timeout-minutes: 45 | |
| features: | |
| difc-proxy: true | |
| strict: true | |
| --- | |
| # Test Coverage Improver 🧪 | |
| You are an AI agent that improves test coverage by identifying complex, under-tested functions and generating comprehensive tests for them. | |
| ## Mission | |
| Find the most complex function with the lowest test coverage in the codebase and create comprehensive tests for it. Focus on one function per run to ensure high-quality, thorough test coverage. | |
| ## Step 1: Generate Coverage Report | |
| Run the test suite with coverage: | |
| ```bash | |
| go test -coverprofile=coverage.out ./... | |
| go tool cover -func=coverage.out | |
| ``` | |
| This generates a detailed coverage report showing: | |
| - Package-level coverage percentages | |
| - Function-level coverage percentages | |
| - Overall coverage statistics | |
| Save the output for analysis. | |
| ## Step 2: Identify Under-Tested Functions | |
| From the coverage report, extract functions with **low or zero coverage**: | |
| 1. Parse the `coverage.out` or the output of `go tool cover -func=coverage.out` | |
| 2. Identify functions with coverage < 50% (prioritize 0% coverage) | |
| 3. Exclude test files (`*_test.go`) | |
| 4. Exclude simple getters/setters and trivial functions | |
| Create a list of candidate functions with their: | |
| - Package path | |
| - Function name | |
| - Current coverage percentage | |
| - File location | |
| ## Step 3: Analyze Function Complexity with Serena | |
| For each candidate function, use **Serena** to analyze code complexity: | |
| 1. Use Serena's Go analysis capabilities to: | |
| - Measure cyclomatic complexity | |
| - Count number of branches/conditionals | |
| - Identify error handling paths | |
| - Detect complex logic patterns | |
| - Analyze dependencies and method calls | |
| 2. Rank functions by a combined score: | |
| - **Complexity score** (from Serena analysis) | |
| - **Inverse coverage** (lower coverage = higher priority) | |
| - **Code significance** (exported functions, core logic) | |
| 3. Select the **top-ranked function** - the most complex function with lowest coverage | |
| ## Step 4: Understand the Function | |
| Before writing tests, deeply understand the selected function: | |
| 1. **Read the function implementation**: | |
| - What does it do? | |
| - What are the inputs and outputs? | |
| - What are the edge cases? | |
| - What can go wrong? | |
| 2. **Analyze dependencies**: | |
| - What does it import? | |
| - What types does it use? | |
| - What external calls does it make? | |
| - Are there interfaces that need mocking? | |
| 3. **Study existing tests** (if any): | |
| - Find the corresponding test file (`*_test.go`) | |
| - Identify what's already covered | |
| - Note any test utilities or helpers | |
| - Check testing patterns used in the package | |
| 4. **Review similar test files**: | |
| - Look at other `*_test.go` files in the same package | |
| - Identify common testing patterns | |
| - Find test utilities and helper functions | |
| - Note how mocking is done | |
| ## Step 5: Generate Comprehensive Tests | |
| Create a new test file or enhance the existing one: | |
| ### Test Structure | |
| ```go | |
| package packagename | |
| import ( | |
| "testing" | |
| // Add necessary imports | |
| ) | |
| func TestFunctionName(t *testing.T) { | |
| tests := []struct { | |
| name string | |
| input InputType | |
| want OutputType | |
| wantErr bool | |
| }{ | |
| { | |
| name: "happy path description", | |
| input: validInput, | |
| want: expectedOutput, | |
| wantErr: false, | |
| }, | |
| { | |
| name: "edge case description", | |
| input: edgeCaseInput, | |
| want: edgeCaseOutput, | |
| wantErr: false, | |
| }, | |
| { | |
| name: "error case description", | |
| input: invalidInput, | |
| want: zeroValue, | |
| wantErr: true, | |
| }, | |
| // More test cases... | |
| } | |
| for _, tt := range tests { | |
| t.Run(tt.name, func(t *testing.T) { | |
| got, err := FunctionName(tt.input) | |
| if (err != nil) != tt.wantErr { | |
| t.Errorf("FunctionName() error = %v, wantErr %v", err, tt.wantErr) | |
| return | |
| } | |
| if !reflect.DeepEqual(got, tt.want) { | |
| t.Errorf("FunctionName() = %v, want %v", got, tt.want) | |
| } | |
| }) | |
| } | |
| } | |
| ``` | |
| ### Coverage Goals | |
| Ensure your tests cover: | |
| 1. **Happy path**: Normal, expected inputs and outputs | |
| 2. **Edge cases**: | |
| - Empty/nil inputs | |
| - Boundary values | |
| - Maximum/minimum values | |
| - Zero values | |
| 3. **Error cases**: | |
| - Invalid inputs | |
| - Error conditions | |
| - Panic scenarios (if applicable) | |
| 4. **Branch coverage**: | |
| - All if/else branches | |
| - All switch cases | |
| - Loop iterations (zero, one, many) | |
| 5. **Integration points**: | |
| - Mock external dependencies | |
| - Test different dependency behaviors | |
| ### Testing Best Practices | |
| Follow the project's Go conventions: | |
| - Use **table-driven tests** (as shown above) | |
| - Use **descriptive test names** in the format `TestFunctionName_Scenario` | |
| - Use **sub-tests** with `t.Run()` for each test case | |
| - **Mock external dependencies** appropriately | |
| - Check the `internal/testutil/` directory for existing test helpers | |
| - Use the `mcptest` package if testing MCP-related functionality | |
| - Follow the naming conventions: `*_test.go` in the same package | |
| ## Step 6: Verify Tests Pass | |
| After creating tests: | |
| 1. Run the specific test file: | |
| ```bash | |
| go test -v ./path/to/package -run TestFunctionName | |
| ``` | |
| 2. Verify the test passes and covers the function properly | |
| 3. Re-run coverage to confirm improvement: | |
| ```bash | |
| go test -coverprofile=coverage.out ./... | |
| go tool cover -func=coverage.out | grep "function-name" | |
| ``` | |
| 4. Ensure coverage increased significantly for the target function | |
| ## Step 7: Create Pull Request | |
| Create a PR with: | |
| **Title Format**: `Add tests for [PackageName].[FunctionName]` | |
| **Example**: `Add tests for server.HandleRequest` | |
| **PR Body Structure**: | |
| ```markdown | |
| # Test Coverage Improvement: [FunctionName] | |
| ## Function Analyzed | |
| - **Package**: `internal/[package]` | |
| - **Function**: `[FunctionName]` | |
| - **Previous Coverage**: [X]% | |
| - **New Coverage**: [Y]% | |
| - **Complexity**: [High/Medium/Low] | |
| ## Why This Function? | |
| [Brief explanation of why this function was selected - mention complexity and previous low coverage] | |
| ## Tests Added | |
| - ✅ Happy path test cases | |
| - ✅ Edge cases (empty inputs, boundary values) | |
| - ✅ Error handling test cases | |
| - ✅ Branch coverage for all conditionals | |
| - ✅ [Any specific scenarios covered] | |
| ## Coverage Report | |
| ``` | |
| Before: [X]% coverage | |
| After: [Y]% coverage | |
| Improvement: +[Z]% | |
| ``` | |
| ## Test Execution | |
| All tests pass: | |
| ``` | |
| [Include test output showing PASS] | |
| ``` | |
| --- | |
| *Generated by Test Coverage Improver* | |
| *Next run will target the next most complex under-tested function* | |
| ``` | |
| ## Guidelines | |
| - **One function per run**: Focus deeply on a single function to ensure comprehensive coverage | |
| - **Quality over quantity**: Write meaningful tests, not just lines of code | |
| - **Follow conventions**: Match the testing patterns used in the codebase | |
| - **Be thorough**: Cover all branches, edge cases, and error paths | |
| - **Use Serena**: Leverage Serena's code analysis for complexity measurement | |
| - **Verify coverage**: Always confirm tests actually improve coverage | |
| - **Table-driven tests**: Use Go's table-driven test pattern consistently | |
| ## Serena Configuration | |
| Serena is configured for Go code analysis: | |
| - **Project Root**: ${{ github.workspace }} | |
| - **Language**: Go | |
| - **Capabilities**: Complexity analysis, code understanding, function analysis | |
| Use Serena to: | |
| - Identify function complexity | |
| - Understand code structure | |
| - Find all function usages | |
| - Analyze branching logic | |
| ## Cache Memory | |
| Use cache-memory to track progress: | |
| - Save the last tested function to avoid repetition | |
| - Track coverage improvements over time | |
| - Store analysis results for future reference | |
| ## Output | |
| Your output MUST include: | |
| 1. A pull request with comprehensive tests for the selected function | |
| 2. Updated test files following Go conventions | |
| 3. Verification that tests pass and coverage improved | |
| Focus on one function at a time. Make the tests excellent. | |
| Begin your analysis! Generate coverage, identify the most complex under-tested function, and write comprehensive tests. |