How to Run Tests in Munder Difflin Using Node's Built-in Test Runner

Run the full test suite in munder-difflin with node --test test/**/*.test.cjs or use the npm run test:focused convenience script.

The munder-difflin repository uses Node.js v18+'s native test runner rather than a third-party framework like Jest or Mocha. This approach eliminates extra dependencies and leverages the --test flag introduced in Node 18. The test files follow the *.test.cjs naming convention and reside in the test/ directory.

Prerequisites

Before running tests, ensure you have:

• Node.js v18 or higher — the native test runner requires this version
• npm — package manager for installing dependencies

The repository also depends on native modules like node-pty, which rebuild automatically during installation via the postinstall script defined in package.json.

Step 1: Clone and Install

Start by cloning the repository and installing dependencies:

git clone https://github.com/chaitanyagiri/munder-difflin.git
cd munder-difflin
npm install

The npm install command triggers the postinstall script in package.json (lines 14–19), which rebuilds native addons including node-pty. This step is essential — skipping it will cause test failures related to terminal emulation.

Step 2: Run the Full Test Suite

Munder difflin offers two equivalent ways to execute all tests:

Option A: Direct Node command (recommended)

node --test test/**/*.test.cjs

Option B: Package.json script

npm run test:focused

The test:focused script in package.json (lines 22–23) wraps the same node --test invocation with an explicit file list. Both methods produce identical TAP-formatted output showing pass (✔) or fail (✖) status for each test.

Step 3: Run Specific Test Files

For faster feedback during development, target individual test files or patterns:

# Single test file

node --test test/hero-payload.test.cjs

# Pattern-based filtering

node --test test/**/skills*.test.cjs
node --test test/*/provider-*.test.cjs

Node's test runner accepts any glob pattern supported by your shell, making it easy to isolate problematic tests without running the entire suite.

Understanding Test Output

The native test runner outputs TAP (Test Anything Protocol) format by default:

• Passing tests display with ✔ and completion time
• Failing tests show ✖ with stack traces
• Exit code 0 indicates success; non-zero indicates failures

Check the exit code explicitly on Unix systems:

node --test test/**/*.test.cjs
echo $?   # 0 = all passed, non-zero = failures detected

Key Configuration Files

Understanding these files helps when customizing test execution:

File	Purpose
package.json	Defines scripts.postinstall for native rebuilds and scripts.test:focused for test execution
test/	Contains all *.test.cjs test files organized by feature
README.md (lines 85–90)	Documents clone and install procedures

The postinstall script is particularly important — it ensures node-pty and other native dependencies are compiled for your specific platform before tests attempt to use them.

Complete Workflow Example

From a fresh environment to verified tests:

# Clone and setup

git clone https://github.com/chaitanyagiri/munder-difflin.git
cd munder-difflin
npm install

# Run all tests

npm run test:focused

# Or run directly with Node

node --test test/**/*.test.cjs

Summary

• Munder difflin uses Node v18+'s native node --test — no Jest, Mocha, or other test runner required
• Install with npm install to trigger native module rebuilds via postinstall
• Execute tests with node --test test/**/*.test.cjs or the npm run test:focused wrapper
• Filter tests using shell globs for faster development cycles
• All test files use the .test.cjs extension and live in the test/ directory

Frequently Asked Questions

What Node version is required to run tests in munder-difflin?

Node.js v18 or higher is required. The repository relies on the native --test flag introduced in Node 18, which provides built-in test running without external dependencies.

Why does npm test not work in this repository?

The package.json does not define a standard test script. Instead, it exposes test:focused as the primary test command. You can run npm run test:focused or invoke node --test directly with your desired file pattern.

What happens if tests fail with errors about node-pty?

This indicates the postinstall script did not complete successfully during npm install. Run npm install again and check for compilation errors in the output. The node-pty native module must be rebuilt for your platform before terminal-related tests can execute.

Can I watch tests and re-run on file changes?

Node's native test runner does not include a watch mode. For automatic re-running, use a file watcher like nodemon or chokidar-cli wrapped around the test command, or rely on your editor's test runner integration.

{
  "mcpServers": {
    "instagit": {
      "command": "npx",
      "args": ["-y", "instagit@latest"]
    }
  }
}