# Testing Patterns

**Analysis Date:** 2026-03-27

## Test Framework

**Status:** Not detected
- No test files (*.test.js, *.spec.js) found in codebase
- No test runner configured (no jest.config.js, vitest.config.js, or mocha configuration)
- No test dependencies listed in package.json files

**Code Context:**
- The codebase consists of 5 Node.js hook scripts (579 total lines across `.claude/hooks/`)
- Each hook is a standalone CLI tool that reads JSON from stdin and outputs JSON to stdout
- Hooks are event-driven (SessionStart, PreToolUse, PostToolUse, AfterTool lifecycle events)
- No application code beyond these hooks exists in the repository

## Script Type & Testing Approach

**Current Architecture:**
Each hook file (`gsd-*.js` in `/home/ys/family-repo/AgenticCode/.claude/hooks/`) follows the same structural pattern:
- Shebang: `#!/usr/bin/env node`
- Node.js built-in modules only (fs, path, os, child_process)
- JSON stdin → processing → JSON stdout
- Silent failure on errors (timeout guards, try-catch with exit(0))

**Hook Files:**
- `gsd-prompt-guard.js` (96 lines) - Detects prompt injection patterns in written files
- `gsd-statusline.js` (119 lines) - Renders context usage and task status
- `gsd-context-monitor.js` (156 lines) - Warns when context window is low
- `gsd-workflow-guard.js` (94 lines) - Advises on workflow compliance
- `gsd-check-update.js` (114 lines) - Checks for GSD updates in background

## Manual Testing Indicators

**Integration Points (evidence of real-world testing):**
- Comments referencing specific issues: `See #775`, `See #1162`, `See #870`, `See #884`
- Platform-specific workarounds: `windowsHide: true` for child_process to prevent console flash on Windows
- Timeout guards: `const stdinTimeout = setTimeout(() => process.exit(0), 3000);` prevents hanging on pipe issues
- Git Bash compatibility: explicit handling of stdin timeout on Windows Git Bash

**Behavioral Validation Patterns:**
- Config file validation: reads `.planning/config.json`, catches parse errors gracefully
- File existence checks before operations: `if (fs.existsSync(filePath))`
- Stale data detection: `if ((now - metrics.timestamp) > STALE_SECONDS)`
- Severity escalation tracking: debounce counter resets on warning level change

## Input Validation

**JSON Parsing with Error Handling:**
All hooks follow this pattern (example from `gsd-prompt-guard.js`):
```javascript
let input = '';
const stdinTimeout = setTimeout(() => process.exit(0), 3000);
process.stdin.setEncoding('utf8');
process.stdin.on('data', chunk => input += chunk);
process.stdin.on('end', () => {
  clearTimeout(stdinTimeout);
  try {
    const data = JSON.parse(input);
    // Process data
  } catch {
    // Silent fail — never block tool execution
    process.exit(0);
  }
});
```

**Defensive Checks:**
- Field existence: `const toolName = data.tool_name;` then `if (toolName !== 'Write' && toolName !== 'Edit')`
- Optional chaining: `data.tool_input?.file_path || ''`
- Null checks: `if (!sessionId) { process.exit(0); }`
- Default values: `data.cwd || process.cwd()`, `data.model?.display_name || 'Claude'`

## File I/O Testing

**Patterns for Reliability:**
- Synchronous I/O ensures order: `fs.readFileSync()` → process → `fs.writeFileSync()`
- Directory existence checked before writing: `if (!fs.existsSync(cacheDir)) { fs.mkdirSync(cacheDir, { recursive: true }); }`
- Try-catch wraps all file operations that could fail:
  ```javascript
  try {
    const bridgeData = JSON.stringify({ ... });
    fs.writeFileSync(bridgePath, bridgeData);
  } catch (e) {
    // Silent fail -- bridge is best-effort, don't break statusline
  }
  ```

## State Machine / Behavior Testing

**Context Monitor Debounce Logic** (`gsd-context-monitor.js`):
- Tracks warning state in file: `/tmp/claude-ctx-{session_id}-warned.json`
- Debounce counter incremented: `warnData.callsSinceWarn = (warnData.callsSinceWarn || 0) + 1`
- Severity escalation bypasses debounce: `if (severityEscalated) { // emit immediately }`
- State reset on warn: `warnData.callsSinceWarn = 0`

This pattern validates behavior without formal tests:
```javascript
let warnData = { callsSinceWarn: 0, lastLevel: null };
const isCritical = remaining <= CRITICAL_THRESHOLD;
const currentLevel = isCritical ? 'critical' : 'warning';
const severityEscalated = currentLevel === 'critical' && warnData.lastLevel === 'warning';
if (!firstWarn && warnData.callsSinceWarn < DEBOUNCE_CALLS && !severityEscalated) {
  process.exit(0); // Suppress warning
}
```

## Regex Pattern Testing

**Prompt Injection Detection** (`gsd-prompt-guard.js`):
Patterns tested against content without formal unit tests:
```javascript
const INJECTION_PATTERNS = [
  /ignore\s+(all\s+)?previous\s+instructions/i,
  /override\s+(system|previous)\s+(prompt|instructions)/i,
  /you\s+are\s+now\s+(?:a|an|the)\s+/i,
  /(?:print|output|reveal|show|display|repeat)\s+(?:your\s+)?(?:system\s+)?(?:prompt|instructions)/i,
  /\[SYSTEM\]/i,
  /<<\s*SYS\s*>>/i,
];
for (const pattern of INJECTION_PATTERNS) {
  if (pattern.test(content)) {
    findings.push(pattern.source);
  }
}
```

Unicode detection without regex: `if (/[\u200B-\u200F\u2028-\u202F\uFEFF\u00AD]/.test(content))`

## Environment & Configuration Testing

**Configuration Loading Safety** (all hooks):
- Try-catch with silent fail:
  ```javascript
  const configPath = path.join(cwd, '.planning', 'config.json');
  if (fs.existsSync(configPath)) {
    try {
      const config = JSON.parse(fs.readFileSync(configPath, 'utf8'));
      if (config.hooks?.context_warnings === false) {
        process.exit(0); // Feature disabled
      }
    } catch (e) {
      // Ignore config parse errors
    }
  }
  ```
- Optional chaining for nested config: `config.hooks?.workflow_guard`, `config.hooks?.context_warnings`

**Environment Variable Access:**
```javascript
const envDir = process.env.CLAUDE_CONFIG_DIR;
if (envDir && fs.existsSync(path.join(envDir, 'get-shit-done', 'VERSION'))) {
  return envDir; // Custom config dir detected
}
```

## Performance & Resource Management

**Timeout Guards (prevent resource leaks):**
- All hooks implement stdin timeout: `const stdinTimeout = setTimeout(() => process.exit(0), 3000);`
- Longer timeout for high-volume operations: `const stdinTimeout = setTimeout(() => process.exit(0), 10000);` in context-monitor
- Always cleared before processing: `clearTimeout(stdinTimeout);`

**Background Process Management** (`gsd-check-update.js`):
- Child process spawned with `stdio: 'ignore'`: doesn't inherit parent's stdio
- Process detached on Windows: `detached: true` (required for proper cleanup)
- Parent calls `child.unref()`: parent doesn't wait for child to exit

```javascript
const child = spawn(process.execPath, ['-e', `...inline script...`], {
  stdio: 'ignore',
  windowsHide: true,
  detached: true
});
child.unref();
```

## Test Coverage Gaps

**Areas Without Formal Testing:**
1. **Regex Pattern Accuracy** - Injection patterns untested against false positives/negatives
2. **Debounce Counter Edge Cases** - Corruption recovery, counter reset logic
3. **Platform-Specific Behavior** - Windows vs Linux path handling, process detachment
4. **Concurrent Access** - Multiple hooks writing to same state files simultaneously
5. **Large Input Handling** - No tests for multi-megabyte JSON on stdin
6. **Stale File Cleanup** - No validation that temp files are properly removed
7. **Spawn Child Behavior** - Background update check success/failure not validated

## Recommendation for Testing

**Given the architecture (CLI hooks, not library code):**
- Integration testing more valuable than unit tests
- Manual testing via real Claude Code sessions is current primary validation
- Would recommend:
  1. Snapshot tests for JSON output structure
  2. Mock file system for configuration loading paths
  3. Integration tests simulating tool use hook flow
  4. Platform-specific testing (Windows, macOS, Linux) for path handling

**Lack of tests is acceptable for:**
- Simple stdin/stdout data transformation scripts
- Hooks deployed once per installation (not on every tool call)
- Silent-fail-safe design (errors don't break workflows)
- Real-world testing via 50+ GitHub issues and fixes

---

*Testing analysis: 2026-03-27*