coffeelint-mocha

CoffeeLint rules for Mocha test framework.

It a port of eslint-plugin-mocha to CoffeeLint.

Installation

To install the package, run:

npm install coffeelint-mocha --save-dev

Example

Add rules to your coffeelint.json:

{
  "handle_done_callback": {
    "module": "coffeelint-mocha/handle_done_callback",
    "level": "error"
  },
  "no_exclusive_tests": {
    "module": "coffeelint-mocha/no_exclusive_tests",
    "level": "error"
  },
  "no_global_tests": {
    "module": "coffeelint-mocha/no_global_tests",
    "level": "error"
  },
  "no_pending_tests": {
    "module": "coffeelint-mocha/no_pending_tests",
    "level": "error"
  },
  "no_skipped_tests": {
    "module": "coffeelint-mocha/no_skipped_tests",
    "level": "error"
  },
  "no_synchronous_tests": {
    "module": "coffeelint-mocha/no_synchronous_tests",
    "level": "error"
  }
}

Rules

`handle_done_callback`

Mocha allows you to write asynchronous tests by adding a done callback to the parameters of your test function. It is easy to forget calling this callback after the asynchronous operation is done.

Example:

// Bad
it('returns a user', function (done) {
  getUser(42)
    .then(function (user) {
      assert.deepEqual(user, {id: 42, name: 'Sasha'})
      // done callback wasn't called
    })
})
 
// Good
it('returns a user', function (done) {
  getUser(42)
    .then(function (user) {
      assert.deepEqual(user, {id: 42, name: 'Sasha'})
      done() // Ok
    })
})
 
// Good
it('returns a user', function (done) {
  getUser(42)
    .then(function (user) {
      assert.deepEqual(user, {id: 42, name: 'Sasha'})
    })
    .then(done) // Ok
})

To start using the rule, add handle_done_callback to your coffeelint.json:

{
  "handle_done_callback": {
    "module": "coffeelint-mocha/handle_done_callback",
    "level": "error"
  }
}

`no_exclusive_tests`

Mocha has a feature that allows you to run tests exclusively by appending .only to a test-suite or a test-case. This feature is really helpful to debug a failing test, so you don’t have to execute all of your tests. After you have fixed your test and before committing the changes you have to remove .only to ensure all tests are executed on your build system.

This rule reminds you to remove .only from your tests by raising an error whenever you are using the exclusivity feature.

Example:

// Bad
it.only('multiples numbers', function () {
  assert.equal(multiply(21, 2), 42)
})
 
// Good
it('multiples numbers', function () {
  assert.equal(multiply(21, 2), 42)
})

To start using the rule, add no_exclusive_tests to your coffeelint.json:

{
  "no_exclusive_tests": {
    "module": "coffeelint-mocha/no_exclusive_tests",
    "level": "error"
  }
}

`no_global_tests`

Mocha gives you the possibility to structure your tests inside of suites using describe, suite or context.

Example:

// Bad
it('multiples numbers', function () {
  assert.equal(multiply(21, 2), 42)
})
 
// Good
describe('multiply', function () {
  it('multiples numbers', function () {
    assert.equal(multiply(21, 2), 42)
  })
})

To start using the rule, add no_global_tests to your coffeelint.json:

{
  "no_global_tests": {
    "module": "coffeelint-mocha/no_global_tests",
    "level": "error"
  }
}

`no_pending_tests`

Mocha allows specification of pending tests, which represent tests that aren't yet implemented, but are intended to be implemented eventually. These are designated like a normal mocha test, but with only the first argument provided (no callback for the actual implementation). For example: it('unimplemented test')

This rule allows you to raise errors on pending tests. This can be useful, for example, for reminding developers that pending tests exist in the repository, so they're more likely to get implemented.

Example:

// Bad
it('multiples numbers')
 
// Good
it('multiples numbers', function () {
  assert.equal(multiply(21, 2), 42)
})

To start using the rule, add no_pending_tests to your coffeelint.json:

{
  "no_pending_tests": {
    "module": "coffeelint-mocha/no_pending_tests",
    "level": "error"
  }
}

`no_skipped_tests`

Mocha has a feature that allows you to skip tests by appending .skip to a test-suite or a test-case, or by prepending it with an x (e.g., xdescribe(...) instead of describe(...)). Sometimes tests are skipped as part of a debugging process, and aren't intended to be committed. This rule reminds you to remove .skip or the x prefix from your tests.

Example:

// Bad
xit('multiples numbers', function () {
  assert.equal(multiply(21, 2), 42)
})
 
// Bad
it.skip('multiples numbers', function () {
  assert.equal(multiply(21, 2), 42)
})
 
// Good
it('multiples numbers', function () {
  assert.equal(multiply(21, 2), 42)
})

To start using the rule, add no_skipped_tests to your coffeelint.json:

{
  "no_skipped_tests": {
    "module": "coffeelint-mocha/no_skipped_tests",
    "level": "error"
  }
}

`no_synchronous_tests`

Mocha automatically determines whether a test is synchronous or asynchronous based on the arity of the function passed into it. When writing tests for a asynchronous function, omitting the done callback or forgetting to return a promise can often lead to false-positive test cases. This rule warns against the implicit synchronous feature, and should be combined with handle_done_callback for best results.

Example:

// Bad
it('multiples numbers', function () {
  assert.equal(multiply(21, 2), 42)
})
 
// Good
it('multiples numbers', function (done) {
  assert.equal(multiply(21, 2), 42)
  done()
})

To start using the rule, add no_synchronous_tests to your coffeelint.json:

{
  "no_synchronous_tests": {
    "module": "coffeelint-mocha/no_synchronous_tests",
    "level": "error"
  }
}