# Roadmap to 100% Test Coverage

## Current State
- **Coverage**: 78.7% (317/403 tests)
- **Quality**: A-grade
- **Technical Debt**: 0

## Milestone 1: 85% Coverage
**Target**: 342/403 tests (+25 tests)
**Timeline**: 2 days

### Tasks
1. **Fix Assertion Failures** (+10 tests)
   - [ ] Fix import test assertions
   - [ ] Update transpiler expectations
   - [ ] Correct spacing issues
   - [ ] Handle edge cases

2. **Enable Disabled Tests** (+10 tests)
   - [ ] Review disabled test files
   - [ ] Update for current API
   - [ ] Fix compilation issues
   - [ ] Validate outputs

3. **Add Error Path Tests** (+5 tests)
   - [ ] Parser error recovery
   - [ ] Invalid syntax handling
   - [ ] Type error messages
   - [ ] Runtime error cases

## Milestone 2: 90% Coverage
**Target**: 363/403 tests (+21 tests)
**Timeline**: 3 days

### Tasks
1. **Implement Set Comprehensions** (+8 tests)
   ```rust
   // Parse: {x for x in items}
   // Output: items.into_iter().collect::<HashSet<_>>()
   ```

2. **Implement Dict Comprehensions** (+8 tests)
   ```rust
   // Parse: {k: v for (k, v) in items}
   // Output: items.into_iter().collect::<HashMap<_, _>>()
   ```

3. **Module System Tests** (+5 tests)
   - [ ] Module declarations
   - [ ] Import resolution
   - [ ] Re-exports
   - [ ] Visibility rules

## Milestone 3: 95% Coverage
**Target**: 383/403 tests (+20 tests)
**Timeline**: 3 days

### Tasks
1. **DataFrame Support** (+10 tests)
   ```rust
   // Parse: df![...]
   // Output: DataFrame::new(...)
   ```

2. **Advanced Keywords** (+5 tests)
   - [ ] `const fun` support
   - [ ] `unsafe fun` support
   - [ ] `pub use` support
   - [ ] `async fun` support

3. **Macro System** (+5 tests)
   - [ ] Custom macros
   - [ ] Macro expansion
   - [ ] Procedural macros
   - [ ] Built-in macros

## Milestone 4: 100% Coverage
**Target**: 403/403 tests (+20 tests)
**Timeline**: 5 days

### Tasks
1. **Complete Parser Coverage** (+10 tests)
   - [ ] All token types
   - [ ] All AST nodes
   - [ ] All precedence levels
   - [ ] All error cases

2. **Complete Transpiler Coverage** (+5 tests)
   - [ ] All Rust features
   - [ ] All optimizations
   - [ ] All target versions
   - [ ] All configurations

3. **Integration Test Suite** (+5 tests)
   - [ ] Full programs
   - [ ] Library usage
   - [ ] Cross-feature interaction
   - [ ] Performance benchmarks

## Implementation Strategy

### Test Quality Standards (MANDATORY)
- **Complexity**: ≤10 per test
- **Lines**: ≤30 per test
- **Single Responsibility**: One assertion focus
- **No Technical Debt**: Zero TODOs
- **Clear Names**: test_specific_behavior_expected_result

### Development Process
1. **Write Test First** (EXTREME TDD)
2. **Verify Failure** (Red)
3. **Minimal Implementation** (Green)
4. **Refactor** (Clean)
5. **Document** (Maintain)

### Coverage Tracking
```bash
# Run after each session
cargo llvm-cov --html
cargo llvm-cov --summary-only

# Track trends
git commit -m "[COVERAGE] Current: X% (+Y%)"
```

## Technical Requirements

### Parser Enhancements Needed
```rust
// Set comprehension support
ExprKind::SetComprehension {
    element: Box<Expr>,
    iter: Box<Expr>,
    filter: Option<Box<Expr>>,
}

// Dict comprehension support
ExprKind::DictComprehension {
    key: Box<Expr>,
    value: Box<Expr>,
    iter: Box<Expr>,
    filter: Option<Box<Expr>>,
}

// DataFrame literal support
ExprKind::DataFrameLiteral {
    columns: Vec<(String, Vec<Expr>)>,
}
```

### Transpiler Extensions Needed
```rust
// Comprehension transpilation
fn transpile_set_comprehension(&self, comp: &SetComprehension) -> TokenStream
fn transpile_dict_comprehension(&self, comp: &DictComprehension) -> TokenStream
fn transpile_dataframe(&self, df: &DataFrameLiteral) -> TokenStream

// Keyword combinations
fn transpile_const_fun(&self, func: &Function) -> TokenStream
fn transpile_unsafe_fun(&self, func: &Function) -> TokenStream
```

## Risk Mitigation

### Potential Blockers
1. **Parser Complexity**
   - Risk: Comprehension syntax conflicts
   - Mitigation: Incremental implementation

2. **Breaking Changes**
   - Risk: Existing tests fail
   - Mitigation: Feature flags

3. **Performance Impact**
   - Risk: Tests slow down
   - Mitigation: Parallel execution

## Success Criteria

### 85% Milestone
- [ ] 342+ tests passing
- [ ] All critical paths tested
- [ ] No complexity >10

### 90% Milestone
- [ ] 363+ tests passing
- [ ] Comprehensions working
- [ ] <5% duplication

### 95% Milestone
- [ ] 383+ tests passing
- [ ] DataFrame support
- [ ] All keywords working

### 100% Milestone
- [ ] 403/403 tests passing
- [ ] Zero technical debt
- [ ] A+ quality grade
- [ ] <1s test runtime

## Timeline Summary

| Milestone | Coverage | Tests Needed | Days | Date Target |
|-----------|----------|--------------|------|-------------|
| Current | 78.7% | - | - | Complete |
| 85% | 85% | +25 | 2 | 2 days |
| 90% | 90% | +21 | 3 | 5 days |
| 95% | 95% | +20 | 3 | 8 days |
| 100% | 100% | +20 | 5 | 13 days |

**Total Timeline**: 13 days to 100% coverage

## Conclusion

Achieving 100% test coverage is realistic and achievable within 2 weeks by:
1. Following EXTREME TDD methodology
2. Maintaining quality standards
3. Systematically addressing blockers
4. Incremental progress tracking

The investment will pay dividends in:
- Code reliability
- Refactoring confidence
- Documentation through tests
- Quality assurance

**Next Step**: Begin 85% milestone tasks immediately.