Writing Tests

All tests are written using tap as our test framework.

Before running any tests make sure you install the cli dev dependencies using the cloned repo itself:

$ cd /path/to/cloned/npm/cli
$ node . install

You may then run all tests:

$ node . test

In order to run a single test, just execute the test file directly:

$ node test/lib/ls.js
# runs `npm ls` tests

If you need files on disk as part of your test, we use tap fixtures to handle that:

var path = require('path')
var t = require('tap')

t.test('test something', t => {
  const path = t.testdir({
    'package.json': JSON.stringify({
      name: 'my-example-package',
      version: '1.0.0'
    })
  })
  t.ok(path, 'should return file path to a folder containing the created fixtures')
})

If you need to mock modules (by modules I mean anything you require), you can use tap.mock.

Using it looks like:

// use t.mock() to require a module while replacing
// its internal required modules for mocked replacements:
const myModule = t.mock('../my-module', {
  'fs': {
    readFileSync: () => throw new Error('oh no')
  },
  '../util/my-helper.js': {
    foo: () => 'bar'
  }
})

// run tests, e.g:
t.equal(myModule.fnThatUsesMyHelper(), 'bar')