# Test Coverage Analysis - Issue 16: Daemon CLI Integration

## Acceptance Criteria Coverage Summary

### ✅ AC2.1: pyrust --daemon forks background process and exits parent
**Test File**: `tests/test_daemon_lifecycle.sh` (Step 2)
**Coverage**: COMPLETE
- Tests daemon startup with `--daemon` flag
- Verifies parent process exits successfully
- Confirms background daemon process is running
- Validates socket file creation at `/tmp/pyrust.sock`
- Validates PID file creation at `/tmp/pyrust.pid`

**Additional Coverage**: `tests/test_daemon_edge_cases.sh` (Test 1)
- Prevents duplicate daemon startup
- Validates "already running" error message

### ✅ AC2.2: pyrust -c '2+3' with daemon returns correct output
**Test File**: `tests/test_daemon_lifecycle.sh` (Steps 3-4)
**Coverage**: COMPLETE
- Basic arithmetic: `2+3` → `5`
- Complex expressions: `10 * 5`, `100 / 4`
- Print statements with newline: `print(42)` → `42\n`
- Multiline code execution
- Variables and expressions

**Additional Coverage**: `tests/test_daemon_edge_cases.sh` (Test 7)
- Multiple rapid sequential requests (10 requests)
- Validates daemon can handle concurrent-like load

### ✅ AC2.3: pyrust --stop-daemon shuts down cleanly
**Test File**: `tests/test_daemon_lifecycle.sh` (Step 5)
**Coverage**: COMPLETE
- Daemon stop command succeeds
- Socket file removed after shutdown
- PID file removed after shutdown
- Daemon process terminated

**Additional Coverage**: `tests/test_daemon_edge_cases.sh` (Test 2)
- Stop daemon when not running (graceful error)

### ✅ AC2.4: Fallback works when daemon not running
**Test File**: `tests/test_daemon_fallback.sh`
**Coverage**: COMPLETE
- Direct execution without daemon: `2+3`, `10 * 5`, `100 - 25`, `50 / 10`
- Print statements via fallback
- Complex multiline programs via fallback
- Fallback after daemon lifecycle (start → execute → stop → execute)

**Additional Coverage**: `tests/test_daemon_edge_cases.sh` (Test 4)
- Stale socket file handling (fallback when socket exists but daemon is not running)

### ✅ AC2.5: Error messages identical for daemon vs direct execution
**Test File**: `tests/test_error_propagation.sh`
**Coverage**: COMPLETE
- Division by zero: identical error messages
- Undefined variable: identical error messages
- Syntax errors: identical error messages
- Exit codes match for both modes

**Additional Coverage**: `tests/test_daemon_edge_cases.sh` (Test 5)
- Complex error scenarios through daemon
- Division by zero with assignment
- Undefined variable in print
- Incomplete expressions

## Edge Cases Coverage

### 1. Empty/Whitespace Input
**Test File**: `tests/test_daemon_edge_cases.sh` (Test 3)
- Empty string: `""`
- Whitespace only: `"   "`
- Newlines only
**Status**: ✅ COVERED

### 2. Daemon State Management
**Test File**: `tests/test_daemon_edge_cases.sh` (Tests 1, 2)
- Double daemon start (should fail)
- Stop when not running (graceful error)
**Status**: ✅ COVERED

### 3. Stale Socket Files
**Test File**: `tests/test_daemon_edge_cases.sh` (Test 4)
- Socket file exists but daemon is not running
- Fallback to direct execution
**Status**: ✅ COVERED

### 4. Daemon Status Monitoring
**Test File**: `tests/test_daemon_edge_cases.sh` (Test 6)
- Status when not running
- Status when running
- Status after stop
**Status**: ✅ COVERED

### 5. Concurrent/Rapid Requests
**Test File**: `tests/test_daemon_edge_cases.sh` (Test 7)
- 10 rapid sequential requests
- All succeed with correct output
**Status**: ✅ COVERED

### 6. Parent-Child Synchronization
**Implementation**: `src/main.rs` (lines 109-150)
- Pipe-based synchronization to prevent race conditions
- Parent waits for child to signal readiness
- Child signals 'R' when ready
**Status**: ✅ IMPLEMENTED AND TESTED (implicitly via lifecycle tests)

### 7. Error Reporting Before Daemon Detachment
**Implementation**: `src/main.rs` (lines 173-184)
- DaemonServer initialization before closing stderr
- Errors can be reported to parent before detachment
**Status**: ✅ IMPLEMENTED (no explicit test, but covered by successful daemon startup)

## Missing Edge Cases (Potential Additions)

### 1. ⚠️ Signal Handling During Execution
**Scenario**: Daemon receives SIGTERM while executing code
**Current Coverage**: Partial (daemon stops, but mid-execution behavior not explicitly tested)
**Recommendation**: Not critical for AC validation

### 2. ⚠️ Socket Permission Errors
**Scenario**: `/tmp/pyrust.sock` cannot be created due to permissions
**Current Coverage**: None (assumes `/tmp` is writable)
**Recommendation**: Not critical (environmental assumption)

### 3. ⚠️ Very Large Input Strings
**Scenario**: Execute code with 10KB+ input
**Current Coverage**: None (only small strings tested)
**Recommendation**: Not critical for AC validation (performance issue, not correctness)

### 4. ⚠️ Unicode/Non-ASCII Input
**Scenario**: Python code with UTF-8 characters
**Current Coverage**: None (only ASCII tested)
**Recommendation**: Not critical (lexer handles UTF-8, but not specifically tested in daemon context)

### 5. ⚠️ Daemon Crash Recovery
**Scenario**: Daemon crashes unexpectedly, stale PID file remains
**Current Coverage**: Partial (stale socket handled, but not stale PID file)
**Recommendation**: Low priority (rare scenario)

## Test Execution Summary

### Shell Integration Tests
1. ✅ `test_daemon_lifecycle.sh` - PASSED
2. ✅ `test_daemon_fallback.sh` - PASSED
3. ✅ `test_error_propagation.sh` - PASSED
4. ✅ `test_daemon_edge_cases.sh` - PASSED

### Results
- **Total ACs**: 5
- **ACs Covered**: 5 (100%)
- **Edge Cases Identified**: 12
- **Edge Cases Covered**: 7 (58% - all critical cases)
- **Missing Coverage**: 5 (all low-priority or environmental)

## Conclusion

**ALL ACCEPTANCE CRITERIA (AC2.1-AC2.5) ARE FULLY COVERED WITH COMPREHENSIVE TESTS**

The existing test suite provides:
1. Complete coverage of all 5 acceptance criteria
2. Extensive edge case testing including error propagation, state management, and fallback behavior
3. Both positive and negative test scenarios
4. Integration tests that validate the full daemon lifecycle

The coder has implemented proper synchronization mechanisms (pipe-based parent-child communication) and error handling (initialization before stderr closure) that address the core issues mentioned in the issue description.

## Recommendations

1. **No additional tests required for AC validation** - all criteria are met
2. Optional: Add stress test for very large inputs (performance validation)
3. Optional: Add test for daemon behavior under resource constraints (memory/CPU)
4. Current test coverage is **production-ready** for the stated acceptance criteria
