jest command not found or not installed

What this failure means

The jest command could not be found. Jest is either not installed as a dependency, not in the PATH, or the wrong shell was used to run it.

Symptoms

Faultline looks for one or more of these log fragments:

jest: command not found
path.*\.bin/jest

Diagnosis

Jest is typically installed locally as a dev dependency and accessed through npm run test or npx jest. Common causes:

• Jest is not listed in package.json as a devDependency.
• npm install or npm ci was not run before the test step, or it failed silently.
• The script is running in a different shell that does not have the PATH updated.
• Jest is installed locally but the script tries to use the global jest command.
• The test step runs before the install step in CI.

The error typically appears as jest: command not found or jest is not installed.

Fix steps

1. Verify Jest is in package.json:

   grep jest package.json
   

2. If missing, add it as a dev dependency:

   npm install --save-dev jest
   

3. Ensure npm install completes before running tests:

   npm install
   npm test
   

4. Use npm run test or npx jest instead of calling jest directly:

   npm run test    # Uses local jest from node_modules
   npx jest        # Also uses local jest
   jest            # May not work if jest is not in PATH
   

5. Check that the CI job runs the test step after the install step:

   steps:
     - uses: actions/checkout@v4
     - uses: actions/setup-node@v3
       with:
         node-version: '18'
     - run: npm install     # Must run BEFORE test
     - run: npm test        # Now jest is available
   

Validation

• npm install completes without errors.
• npm run test or npx jest executes tests successfully.
• npm ls jest shows jest is installed in node_modules.

Why it matters

Missing test runners block the entire test pipeline. Test failures cannot be diagnosed if the test command itself fails to run.

Prevention

• Always run npm install (or npm ci) before test steps in CI.
• Use npm run test instead of calling commands directly.
• Document the test command in package.json and README.md.
• Commit package-lock.json to ensure consistent installs.

Try it locally

npm install
npm run test
npm ls jest
npm ls jest
npm test

How Faultline detects it

Use faultline explain jest-command-not-found to see the full playbook.

faultline analyze build.log
faultline explain jest-command-not-found

Generated from playbooks/bundled/log/test/jest-command-not-found.yaml. Do not edit directly.