Windows and Git Bash Testing Compatibility Guide

Overview

This guide provides essential knowledge for running Vitest, Playwright, and MSW tests on Windows, particularly in Git Bash/MINGW environments. It addresses common path conversion issues, shell detection, and cross-platform test execution patterns.

Shell Detection in Test Environments

Detecting Git Bash/MINGW

When running tests in Git Bash or MINGW environments, use these detection methods:

Method 1: Environment Variable (Most Reliable)

// Detect Git Bash/MINGW in Node.js test setup
function isGitBash() {
  return !!(process.env.MSYSTEM); // MINGW64, MINGW32, MSYS
}

function isWindows() {
  return process.platform === 'win32';
}

function needsPathConversion() {
  return isWindows() && isGitBash();
}

Method 2: Using uname in Setup Scripts

# In bash test setup scripts
case "$(uname -s)" in
  MINGW64*|MINGW32*|MSYS_NT*)
    # Git Bash/MINGW environment
    export TEST_ENV="mingw"
    ;;
  CYGWIN*)
    # Cygwin environment
    export TEST_ENV="cygwin"
    ;;
  Linux*)
    export TEST_ENV="linux"
    ;;
  Darwin*)
    export TEST_ENV="macos"
    ;;
esac

Method 3: Combined Detection for Test Configuration

// vitest.config.js or test setup
import { execSync } from 'child_process';

function detectShell() {
  // Check MSYSTEM first (most reliable for Git Bash)
  if (process.env.MSYSTEM) {
    return { type: 'mingw', subsystem: process.env.MSYSTEM };
  }

  // Try uname if available
  try {
    const uname = execSync('uname -s', { encoding: 'utf8' }).trim();
    if (uname.startsWith('MINGW')) return { type: 'mingw' };
    if (uname.startsWith('CYGWIN')) return { type: 'cygwin' };
    if (uname === 'Darwin') return { type: 'macos' };
    if (uname === 'Linux') return { type: 'linux' };
  } catch {
    // uname not available (likely Windows cmd/PowerShell)
  }

  return { type: 'unknown', platform: process.platform };
}

const shell = detectShell();
console.log('Running tests in:', shell.type);

Path Conversion Issues and Solutions

Common Path Conversion Problems

Git Bash automatically converts Unix-style paths to Windows paths, which can cause issues with test file paths, module imports, and test configuration.

Problem Examples:

# Git Bash converts these automatically:
/foo → C:/Program Files/Git/usr/foo
/foo:/bar → C:\msys64\foo;C:\msys64\bar
--dir=/foo → --dir=C:/msys64/foo

Solution 1: Disable Path Conversion

For test commands where path conversion causes issues:

# Disable all path conversion for a single command
MSYS_NO_PATHCONV=1 vitest run

# Disable for specific patterns
export MSYS2_ARG_CONV_EXCL="--coverage.reporter"
vitest run --coverage.reporter=html

# Disable for entire test session
export MSYS_NO_PATHCONV=1
npm test

Solution 2: Use Native Windows Paths in Configuration

When specifying test file paths in configuration, use Windows-style paths:

// vitest.config.js - Windows-compatible
export default defineConfig({
  test: {
    include: [
      'tests/unit/**/*.test.js',     // Relative paths work best
      'tests/integration/**/*.test.js'
    ],
    // Avoid absolute paths starting with /c/ or C:
    setupFiles: ['./tests/setup.js'], // Use relative paths
    coverage: {
      reportsDirectory: './coverage'  // Relative, not absolute
    }
  }
});

Solution 3: Path Conversion Helper for Test Utilities

Create a helper for converting paths in test utilities:

// tests/helpers/paths.js
import { execSync } from 'child_process';

/**
 * Convert Windows path to Unix path for Git Bash compatibility
 */
export function toUnixPath(windowsPath) {
  if (!needsPathConversion()) return windowsPath;

  try {
    // Use cygpath if available
    return execSync(`cygpath -u "${windowsPath}"`, {
      encoding: 'utf8'
    }).trim();
  } catch {
    // Fallback: manual conversion
    // C:\Users\foo → /c/Users/foo
    return windowsPath
      .replace(/\\/g, '/')
      .replace(/^([A-Z]):/, (_, drive) => `/${drive.toLowerCase()}`);
  }
}

/**
 * Convert Unix path to Windows path
 */
export function toWindowsPath(unixPath) {
  if (!needsPathConversion()) return unixPath;

  try {
    return execSync(`cygpath -w "${unixPath}"`, {
      encoding: 'utf8'
    }).trim();
  } catch {
    // Fallback: manual conversion
    // /c/Users/foo → C:\Users\foo
    return unixPath
      .replace(/^\/([a-z])\//, (_, drive) => `${drive.toUpperCase()}:\\`)
      .replace(/\//g, '\\');
  }
}

function needsPathConversion() {
  return !!(process.env.MSYSTEM ||
           (process.platform === 'win32' && process.env.TERM === 'cygwin'));
}

Usage in Tests:

import { toUnixPath, toWindowsPath } from '../helpers/paths.js';

test('loads config file', () => {
  const configPath = toWindowsPath('/c/project/config.json');
  const config = loadConfig(configPath);
  expect(config).toBeDefined();
});

Test Execution Best Practices for Windows/Git Bash

1. NPM Scripts for Cross-Platform Compatibility

Define test scripts in package.json that work across all environments:

{
  "scripts": {
    "test": "vitest run",
    "test:unit": "vitest run tests/unit",
    "test:integration": "vitest run tests/integration",
    "test:watch": "vitest watch",
    "test:coverage": "vitest run --coverage",
    "test:e2e": "playwright test",
    "test:e2e:headed": "playwright test --headed",
    "test:debug": "vitest run --reporter=verbose"
  }
}

Always use npm scripts rather than direct vitest/playwright commands - this ensures consistent behavior across shells.

2. Relative Path Imports

Use relative paths in test files to avoid path conversion issues:

// ✅ Good - Relative paths work everywhere
import { myFunction } from '../../src/utils.js';
import { server } from '../mocks/server.js';

// ❌ Bad - Absolute paths can cause issues in Git Bash
import { myFunction } from '/c/project/src/utils.js';

3. Test File Discovery

Vitest and Playwright handle file patterns differently in Git Bash:

// vitest.config.js - Use glob patterns, not absolute paths
export default defineConfig({
  test: {
    // ✅ Good - Glob patterns work cross-platform
    include: ['tests/**/*.test.js', 'src/**/*.test.js'],

    // ❌ Bad - Absolute paths problematic in Git Bash
    include: ['/c/project/tests/**/*.test.js']
  }
});

// playwright.config.js - Relative directory paths
export default defineConfig({
  // ✅ Good
  testDir: './tests/e2e',

  // ❌ Bad
  testDir: '/c/project/tests/e2e'
});

4. Temporary File Handling

Git Bash uses Unix-style temp directories, which can cause issues:

// tests/setup.js - Cross-platform temp file handling
import os from 'os';
import path from 'path';

function getTempDir() {
  const tmpdir = os.tmpdir();

  // In Git Bash, os.tmpdir() may return Windows path
  // Ensure it's usable by your test framework
  if (process.env.MSYSTEM && !tmpdir.startsWith('/')) {
    // Convert Windows temp path if needed
    return tmpdir.replace(/\\/g, '/');
  }

  return tmpdir;
}

// Use in tests
const testTempDir = path.join(getTempDir(), 'my-tests');

Playwright-Specific Windows/Git Bash Considerations

1. Browser Installation in Git Bash

# Use npx to ensure correct path handling
npx playwright install

# If issues occur, use Windows-native command prompt instead
# Then run tests from Git Bash

2. Headed Mode in MINGW

When running headed tests in Git Bash, ensure DISPLAY variables are not set:

# Unset DISPLAY if set (can interfere with Windows GUI)
unset DISPLAY

# Run headed tests
npx playwright test --headed

3. Screenshot and Video Paths

Use relative paths for artifacts:

// playwright.config.js
export default defineConfig({
  use: {
    // ✅ Good - Relative paths
    screenshot: 'only-on-failure',
    video: 'retain-on-failure',
  },
  // Output directory with relative path
  outputDir: './test-results',
});

MSW (Mock Service Worker) in Git Bash

MSW generally works without issues in Git Bash, but be aware of:

1. Handler File Imports

Use relative imports in MSW setup:

// tests/mocks/server.js
// ✅ Good
import { handlers } from './handlers.js';

// ❌ Bad - Avoid absolute paths
import { handlers } from '/c/project/tests/mocks/handlers.js';

2. Fetch Polyfill (Node.js)

Ensure Node.js version 18+ for native Fetch API support:

# Check Node version
node --version  # Should be 18+

# If using older Node, MSW 2.x won't work properly

Common Windows/Git Bash Test Errors and Fixes

Error 1: "No such file or directory" in Git Bash

Symptom:

Error: /usr/bin/bash: line 1: C:UsersUsername...No such file

Cause: Path conversion issue, often with temp directories.

Fix:

# Option 1: Disable path conversion
MSYS_NO_PATHCONV=1 npm test

# Option 2: Use Claude Code's Git Bash path variable
export CLAUDE_CODE_GIT_BASH_PATH="C:\\Program Files\\git\\bin\\bash.exe"

# Option 3: Run via npm scripts (recommended)
npm test  # npm handles path issues automatically

Error 2: Module Import Failures

Symptom:

Error: Cannot find module '../src/utils'

Cause: Path separator confusion (backslash vs forward slash).

Fix:

// Use path.join() or path.resolve() for cross-platform paths
import path from 'path';

const utilsPath = path.resolve(__dirname, '../src/utils.js');
const utils = await import(utilsPath);

Error 3: Playwright Browser Launch Failure

Symptom:

Error: Failed to launch browser

Cause: Git Bash environment variables interfering with browser launch.

Fix:

# Clear problematic environment variables
unset DISPLAY
unset BROWSER

# Run Playwright tests
npx playwright test

Error 4: Coverage Report Path Issues

Symptom:

Error: Failed to write coverage to /c/project/coverage

Fix:

// vitest.config.js - Use relative paths
export default defineConfig({
  test: {
    coverage: {
      // ✅ Good
      reportsDirectory: './coverage',

      // ❌ Bad
      reportsDirectory: '/c/project/coverage'
    }
  }
});

Testing Strategy for Multi-Platform Support

1. CI/CD Configuration

Test on multiple platforms in CI/CD:

# .github/workflows/test.yml
name: Tests
on: [push, pull_request]

jobs:
  test:
    strategy:
      matrix:
        os: [ubuntu-latest, windows-latest, macos-latest]
        node: [18, 20, 22]
    runs-on: ${{ matrix.os }}

    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: ${{ matrix.node }}

      - run: npm ci
      - run: npm test
      - run: npm run test:e2e
        if: matrix.os == 'ubuntu-latest'  # Run E2E on Linux only

2. Shell-Specific Test Setup

Create shell-specific setup if needed:

// tests/setup.js
import { detectShell } from './helpers/shell-detect.js';

const shell = detectShell();

// Apply shell-specific configuration
if (shell.type === 'mingw') {
  console.log('Running in Git Bash/MINGW environment');
  // Apply MINGW-specific test setup
  process.env.FORCE_COLOR = '1'; // Enable colors in Git Bash
}

// Standard setup continues...

3. Path-Safe Test Utilities

Create test utilities that work across all platforms:

// tests/helpers/test-utils.js
import path from 'path';
import { fileURLToPath } from 'url';
import { dirname } from 'path';

// Get __dirname equivalent in ESM
export function getCurrentDir(importMetaUrl) {
  return dirname(fileURLToPath(importMetaUrl));
}

// Cross-platform path joining
export function testPath(...segments) {
  return path.join(...segments).replace(/\\/g, '/');
}

// Usage in test file:
// const __dirname = getCurrentDir(import.meta.url);
// const fixturePath = testPath(__dirname, 'fixtures', 'data.json');

Quick Reference

Shell Detection Commands

# Check if running in Git Bash
echo $MSYSTEM           # MINGW64, MINGW32, or empty

# Check OS type
uname -s               # MINGW64_NT-* for Git Bash

# Check platform in Node
node -p process.platform  # win32 on Windows

Path Conversion Quick Fixes

# Disable for single command
MSYS_NO_PATHCONV=1 vitest run

# Disable for session
export MSYS_NO_PATHCONV=1

# Convert path manually
cygpath -u "C:\path"    # Windows → Unix
cygpath -w "/c/path"    # Unix → Windows

Recommended Test Execution (Git Bash on Windows)

# ✅ Best - Use npm scripts
npm test
npm run test:e2e

# ✅ Good - With path conversion disabled
MSYS_NO_PATHCONV=1 vitest run

# ⚠️ Caution - Direct vitest command may have issues
vitest run  # May encounter path conversion issues

Resources

• Git Bash Path Conversion
• Vitest Configuration
• Playwright on Windows
• MSW Node.js Integration

Summary

When running tests on Windows with Git Bash:

1. Use npm scripts for all test execution (most reliable)
2. Use relative paths in configuration and imports
3. Detect shell environment when needed for conditional setup
4. Disable path conversion (MSYS_NO_PATHCONV=1) if issues occur
5. Test on multiple platforms in CI/CD to catch platform-specific issues
6. Avoid absolute paths starting with /c/ or C:\ in test files
7. Use path.join() for programmatic path construction

Following these practices ensures tests run reliably across Windows Command Prompt, PowerShell, Git Bash, and Unix-like environments.