# Test Coverage Expansion Roadmap

**Project:** TracerTM Python Backend
**Current Coverage:** 6.37x test-to-source ratio (201,675 test lines vs 31,678 source lines)
**Goal:** Achieve 100% service coverage and 80%+ error path coverage
**Timeline:** 4-6 weeks

---

## Current State Assessment

### Strengths
✓ 7,500+ unit tests
✓ 2,500+ integration tests
✓ 95.1% docstring coverage
✓ 72% mocking coverage
✓ 50% async test coverage
✓ 43 edge case test files
✓ Comprehensive fixtures (460+ lines)

### Weaknesses
✗ 5 services untested (92.6% coverage)
✗ 25.6% error path coverage (should be 80%+)
✗ 1.2% parameterized tests (should be 20%+)
✗ No GitHub/Jira integration tests
✗ No event service tests
✗ No query optimization tests

---

## Phase 1: Critical Gaps (Week 1-2)

### 1.1 Event Service Tests (16 hours)

**File:** `tests/unit/services/test_event_service_comprehensive.py`

**Test Categories:**
- Event Creation (5 tests)
- Event Retrieval (6 tests)
- Event Filtering (2 tests)
- Event Replay (3 tests)
- Concurrency Handling (2 tests)
- Validation (6 tests)
- Archival/Cleanup (3 tests)

**Expected Tests:** 27-30
**Acceptance Criteria:**
- All test methods pass
- 100% function coverage
- Error paths tested with pytest.raises
- Async operations properly marked
- Fixtures properly defined

**Status Tracking:**
```
[ ] Create test file structure
[ ] Implement creation tests
[ ] Implement retrieval tests
[ ] Implement filtering tests
[ ] Implement replay tests
[ ] Implement concurrency tests
[ ] Implement validation tests
[ ] Run tests - verify pass rate
[ ] Generate coverage report
```

---

### 1.2 GitHub Integration Tests (16 hours)

**File:** `tests/integration/test_github_integration_comprehensive.py`

**Test Categories:**
- Authentication Flow (5 tests)
- Repository Import (3 tests)
- Rate Limiting (3 tests)
- Conflict Resolution (2 tests)
- Data Mapping (2 tests)
- Network Resilience (4 tests)

**Expected Tests:** 19-20
**Acceptance Criteria:**
- GitHub API mocking works correctly
- Authentication errors handled
- Rate limit retries function
- Network errors logged and recovered
- Data mapping accurate
- All error paths covered

**Status Tracking:**
```
[ ] Set up GitHub API mocks
[ ] Implement auth tests
[ ] Implement import tests
[ ] Implement rate limit tests
[ ] Implement conflict tests
[ ] Implement mapping tests
[ ] Implement resilience tests
[ ] Run tests - verify pass rate
[ ] Generate coverage report
```

---

### 1.3 Jira Integration Tests (12 hours)

**File:** `tests/integration/test_jira_integration_comprehensive.py`

**Test Categories:**
- Authentication Flow (4 tests)
- Issue Import (3 tests)
- Field Mapping (2 tests)
- Status Transitions (2 tests)
- Error Handling (3 tests)

**Expected Tests:** 14-15
**Acceptance Criteria:**
- Jira API authentication tested
- Issue import workflow validated
- Field mapping verified
- Status workflow tested
- Error scenarios covered

---

### 1.4 Exception Path Enhancement (12 hours)

**Target:** Add 500+ `pytest.raises` assertions across existing tests

**Files to Update:**
- All service test files (30+ files)
- Repository tests (15+ files)
- Model tests (20+ files)
- CLI tests (12+ files)

**Pattern Implementation:**
```python
# For each method, add:
async def test_method_with_none_input():
    with pytest.raises(ValueError, match="param required"):
        await service.method(param=None)

async def test_method_with_invalid_input():
    with pytest.raises(ValueError, match="invalid"):
        await service.method(param="invalid")

async def test_method_database_error():
    with pytest.raises(DatabaseError):
        await service.method(...)  # when DB fails
```

**Acceptance Criteria:**
- Each method has 2-3 error path tests
- All pytest.raises assertions use descriptive messages
- Error handling verified end-to-end
- 500+ new assertions added

---

## Phase 2: Important Improvements (Week 3)

### 2.1 Query Optimization Service Tests (12 hours)

**File:** `tests/unit/services/test_query_optimization_service_comprehensive.py`

**Test Categories:**
- Query Analysis (4 tests)
- Index Usage Verification (3 tests)
- Query Plan Caching (3 tests)
- Performance Baseline (4 tests)
- Optimization Recommendations (3 tests)

**Expected Tests:** 17-20

---

### 2.2 View Registry Service Tests (8 hours)

**File:** `tests/unit/services/test_view_registry_service_comprehensive.py`

**Test Categories:**
- View Registration (3 tests)
- Dynamic Loading (2 tests)
- Plugin Lifecycle (3 tests)
- View Resolution (2 tests)
- Conflict Resolution (2 tests)

**Expected Tests:** 12-15

---

### 2.3 Parameterization Enhancement (16 hours)

**Target:** Increase from 1.2% to 20% (100+ parameterized test functions)

**Files to Update:**
- Validation tests (30+ updates)
- Edge case tests (20+ updates)
- Boundary tests (20+ updates)
- Error tests (20+ updates)

**Pattern:**
```python
@pytest.mark.parametrize("input,expected_error", [
    (None, ValueError),
    ("", ValueError),
    ({}, ValueError),
    ("invalid", ValueError),
])
async def test_validation(input, expected_error):
    with pytest.raises(expected_error):
        await service.validate(input)
```

**Acceptance Criteria:**
- 100+ functions converted to parameterized
- 3-5 parameter sets per function
- Comprehensive edge case coverage
- Reduced code duplication

---

## Phase 3: Enhancement (Week 4-6)

### 3.1 Property-Based Testing (12 hours)

**Tool:** Hypothesis

**Target Files:**
- Validation tests
- Data transformation tests
- Algorithm tests

**Example:**
```python
from hypothesis import given
import hypothesis.strategies as st

@given(st.text(), st.text())
async def test_link_creation_invariant(source_id, target_id):
    if source_id != target_id:
        link = await service.create_link(source_id, target_id)
        assert link is not None
        assert link.source_id == source_id
```

---

### 3.2 Performance Baseline Establishment (8 hours)

**Create:** `tests/performance/test_performance_baselines.py`

**Metrics to Track:**
- Item CRUD latency (<100ms)
- Link creation latency (<50ms)
- Bulk import throughput (>1000 items/sec)
- Search latency (<500ms)
- Concurrent operations (1000+ simultaneous)

---

### 3.3 Mutation Testing (8 hours)

**Tool:** mutmut

**Setup:**
```bash
pip install mutmut
mutmut run --paths-to-mutate=src/tracertm
mutmut results
```

**Target:** 80%+ mutation score

---

## Detailed Task Breakdown

### Week 1

#### Monday
- [ ] Create Event Service test file (4 hours)
- [ ] Implement event creation tests (2 hours)
- [ ] Implement event retrieval tests (2 hours)
- **Total: 8 hours**

#### Tuesday
- [ ] Complete event filtering/replay/validation tests (4 hours)
- [ ] Complete event concurrency/archival tests (2 hours)
- [ ] Run event service tests (1 hour)
- [ ] Create GitHub integration test file (2 hours)
- **Total: 9 hours**

#### Wednesday-Thursday
- [ ] Complete GitHub integration tests (10 hours)
- [ ] Create Jira integration test file (2 hours)
- [ ] Implement Jira tests (4 hours)
- **Total: 16 hours**

#### Friday
- [ ] Begin exception path enhancement (4 hours)
- [ ] Update 10 test files with error assertions (4 hours)
- [ ] Review and consolidate week 1 (2 hours)
- **Total: 10 hours**

**Week 1 Summary: 43 hours**

### Week 2

#### Focus: Exception Path Enhancement & Parameterization

- [ ] Update remaining 30+ test files with error assertions (20 hours)
- [ ] Generate exception coverage report (2 hours)
- [ ] Convert first 25 test functions to parameterized (8 hours)
- [ ] Review and test (4 hours)

**Week 2 Summary: 34 hours**

### Week 3

#### Focus: Query & View Registry Tests + Parameterization Completion

- [ ] Create Query Optimization service tests (12 hours)
- [ ] Create View Registry service tests (8 hours)
- [ ] Complete parameterization (16 hours)
- [ ] Testing and validation (4 hours)

**Week 3 Summary: 40 hours**

### Week 4-6

#### Focus: Enhancement Features

- [ ] Property-based testing setup and tests (12 hours)
- [ ] Performance baseline establishment (8 hours)
- [ ] Mutation testing setup and analysis (8 hours)
- [ ] Final review and optimization (12 hours)

**Weeks 4-6 Summary: 40 hours**

---

## Success Metrics

### Coverage Targets

| Metric | Before | Target | Status |
|--------|--------|--------|--------|
| Service Coverage | 92.6% | 100% | |
| Error Path Tests | 25.6% | 80%+ | |
| Parameterized Tests | 1.2% | 20%+ | |
| Total Test Lines | 201,675 | 250,000+ | |
| Test Count | 15,000+ | 18,000+ | |

### Quality Targets

| Metric | Before | Target | Status |
|--------|--------|--------|--------|
| Test Pass Rate | 100% | 100% | |
| Docstring Coverage | 95.1% | 95%+ | |
| Fixture Usage | 47.8% | 50%+ | |
| Mocking Coverage | 72% | 75%+ | |
| Async Tests | 50.3% | 55%+ | |

---

## Dependencies & Prerequisites

### Required Packages (Verify Installed)
```bash
pytest>=9.0.0
pytest-asyncio>=1.3.0
pytest-cov>=7.0.0
pytest-mock>=3.15.0
hypothesis>=6.148.0
faker>=38.0.0
PyGithub>=2.1.1  # For GitHub API
jira>=3.0.0       # For Jira API
mutmut>=2.4.3     # For mutation testing
```

### Setup Commands
```bash
# Install test dependencies
pip install -e ".[test]"

# Install additional packages
pip install PyGithub jira mutmut hypothesis

# Verify installation
pytest --version
python -c "import hypothesis; print(hypothesis.__version__)"
```

---

## Execution Instructions

### Daily Workflow

1. **Review Status**
   ```bash
   # Check git status
   git status

   # View coverage from previous run
   cat htmlcov/status.txt 2>/dev/null || echo "No coverage report yet"
   ```

2. **Run Existing Tests First**
   ```bash
   # Run unit tests for modified modules
   pytest tests/unit/services/ -v --tb=short

   # Run affected integration tests
   pytest tests/integration/ -v --tb=short
   ```

3. **Write New Tests**
   - Follow patterns in `COVERAGE_GAP_IMPLEMENTATION_GUIDE.md`
   - Use provided fixtures from `conftest.py`
   - Maintain consistent naming: `test_[method]_[scenario]`

4. **Run Coverage Report**
   ```bash
   # Generate HTML coverage report
   pytest --cov=src/tracertm --cov-report=html tests/unit tests/integration

   # View in browser
   open htmlcov/index.html
   ```

5. **Commit Progress**
   ```bash
   # Stage new tests
   git add tests/unit/services/test_*.py tests/integration/test_*.py

   # Commit with meaningful message
   git commit -m "Add tests for [service]: [number] new tests"

   # Push branch
   git push origin feature/test-coverage-expansion
   ```

---

## CI/CD Integration

### GitHub Actions Workflow

```yaml
name: Test Coverage Report

on: [pull_request, push]

jobs:
  coverage:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v3
      - uses: actions/setup-python@v4
        with:
          python-version: '3.12'

      - name: Install dependencies
        run: pip install -e ".[test]"

      - name: Run tests with coverage
        run: pytest --cov=src/tracertm --cov-report=xml

      - name: Upload coverage
        uses: codecov/codecov-action@v3
        with:
          files: ./coverage.xml
```

---

## Rollback & Contingency

### If Tests Fail

1. **Identify Failure Type**
   ```bash
   pytest tests/unit/services/test_*.py -v --tb=long
   ```

2. **Debug Using Fixtures**
   - Check fixture setup in `conftest.py`
   - Verify mock configuration
   - Add print statements or use pdb

3. **Verify Assumptions**
   - Run individual test: `pytest test_file.py::test_function -v`
   - Check if test passes in isolation
   - Identify external dependencies

4. **Document Issue & Escalate**
   - Create issue in tracking system
   - Document exact error
   - Skip test with reason if necessary

---

## Documentation Updates

### Update These Files as Needed

1. **PYTHON_BACKEND_COVERAGE_REPORT.md**
   - Update metrics as tests are added
   - Document discovered issues
   - Add new test file descriptions

2. **COVERAGE_GAP_IMPLEMENTATION_GUIDE.md**
   - Add patterns for newly discovered gaps
   - Document mock setup for new services
   - Add troubleshooting notes

3. **Test README**
   - Update test count
   - Document new test patterns
   - Add running instructions for new tests

---

## Risk Assessment & Mitigation

### Risk 1: Breaking Existing Tests
**Probability:** Medium
**Impact:** High
**Mitigation:**
- Run full test suite after each change
- Use feature branches
- Get code review before merge

### Risk 2: Mock Complexity
**Probability:** Medium
**Impact:** Medium
**Mitigation:**
- Use provided mock factories
- Document mock setup patterns
- Share mock utilities via conftest.py

### Risk 3: Timeline Overrun
**Probability:** Low
**Impact:** Medium
**Mitigation:**
- Track hours daily
- Prioritize critical gaps (Phase 1)
- Can defer Phase 3 if needed

### Risk 4: External Service Unavailability
**Probability:** Low
**Impact:** Low
**Mitigation:**
- Use mock/stub implementation
- Document required credentials
- Provide setup guide

---

## Sign-Off & Completion

### Acceptance Criteria

When all items below are complete, coverage expansion is approved:

- [ ] All 5 gap services have tests
- [ ] Event Service: 27+ tests passing
- [ ] GitHub Integration: 19+ tests passing
- [ ] Jira Integration: 14+ tests passing
- [ ] 500+ error path assertions added
- [ ] Exception path coverage: 25.6% → 80%+
- [ ] Service coverage: 92.6% → 100%
- [ ] All tests passing (100%)
- [ ] Coverage report generated
- [ ] Documentation updated
- [ ] Code review approved
- [ ] Merged to main branch

### Final Verification

```bash
# Generate final report
pytest --cov=src/tracertm --cov-report=html tests/

# Verify metrics
echo "Total Test Files:"
find tests/unit tests/integration -name "test_*.py" | wc -l

echo "Total Tests:"
pytest tests/unit tests/integration --co -q | tail -1

echo "Pass Rate:"
pytest tests/unit tests/integration -v --tb=no | tail -5
```

---

## Contact & Support

**Questions or Blockers?**
- Review implementation guide patterns
- Check conftest.py for available fixtures
- Consult coverage report for gaps
- Escalate blockers with details

**Version Control:**
- Branch: `feature/test-coverage-expansion`
- Merge Strategy: Squash commits by module
- Review: 1 approval required

