Merge branch 'master' into prefer-to-be-undefined

.travis.yml

@@ -1,11 +1,18 @@
 language: node_js
 node_js:
- - node
- - 8
- - 6
- - 4
+- 8
+- node
+- 6
+- 4
+before_install: yarn global add greenkeeper-lockfile@1
+before_script: greenkeeper-lockfile-update
+after_script: greenkeeper-lockfile-upload
 cache:
  yarn: true
 branches:
- only:
- - master
+ only:
+ - master
+ - "/^greenkeeper/.*$/"
+env:
+ global:
+ secure: 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

README.md

@@ -1,8 +1,15 @@
-# eslint-plugin-jest
-
-[![Build Status](https://travis-ci.org/jest-community/eslint-plugin-jest.svg?branch=master)](https://travis-ci.org/jest-community/eslint-plugin-jest)
-
-Eslint plugin for Jest
+[![Build Status](https://travis-ci.org/jest-community/eslint-plugin-jest.svg?branch=master)](https://travis-ci.org/jest-community/eslint-plugin-jest) [![Greenkeeper badge](https://badges.greenkeeper.io/jest-community/eslint-plugin-jest.svg)](https://greenkeeper.io/)
+
+<div align="center">
+ <a href="https://eslint.org/">
+ <img width="150" height="150" src="https://eslint.org/img/logo.svg">
+ </a>
+ <a href="https://facebook.github.io/jest/">
+ <img width="150" height="150" vspace="" hspace="25" src="https://cdn.worldvectorlogo.com/logos/jest.svg">
+ </a>
+ <h1>eslint-plugin-jest</h1>
+ <p>ESLint plugin for Jest</p>
+</div>
 
 ## Installation
 
@@ -55,6 +62,8 @@ You can also whitelist the environment variables provided by Jest by doing:
 * [no-focused-tests](/docs/rules/no-focused-tests.md) - disallow focused tests.
 * [no-identical-title](/docs/rules/no-identical-title.md) - disallow identical
  titles.
+* [prefer-to-be-null](/docs/rules/prefer-to-be-null.md) - suggest using
+ `toBeNull()`.
 * [prefer-to-be-undefined](/docs/rules/prefer-to-be-undefined.md) - suggest
  using `toBeUndefined()`.
 * [prefer-to-have-length](/docs/rules/prefer-to-have-length.md) - suggest using

docs/rules/prefer-to-be-null.md

@@ -0,0 +1,28 @@
+# Suggest using `toBeNull()` (prefer-to-be-null)
+
+In order to have a better failure message, `toBeNull()` should be used upon
+asserting expections on null value.
+
+## Rule details
+
+This rule triggers a warning if `toBe()` is used to assert a null value.
+
+```js
+expect(null).toBe(null);
+```
+
+This rule is enabled by default.
+
+### Default configuration
+
+The following pattern is considered warning:
+
+```js
+expect(null).toBe(null);
+```
+
+The following pattern is not warning:
+
+```js
+expect(null).toBeNull();
+```

index.js

@@ -3,6 +3,7 @@
 const noDisabledTests = require('./rules/no_disabled_tests');
 const noFocusedTests = require('./rules/no_focused_tests');
 const noIdenticalTitle = require('./rules/no_identical_title');
+const preferToBeNull = require('./rules/prefer_to_be_null');
 const preferToBeUndefined = require('./rules/prefer_to_be_undefined');
 const preferToHaveLength = require('./rules/prefer_to_have_length');
 const validExpect = require('./rules/valid_expect');
@@ -46,6 +47,7 @@ module.exports = {
  'no-disabled-tests': noDisabledTests,
  'no-focused-tests': noFocusedTests,
  'no-identical-title': noIdenticalTitle,
+ 'prefer-to-be-null': preferToBeNull,
  'prefer-to-be-undefined': preferToBeUndefined,
  'prefer-to-have-length': preferToHaveLength,
  'valid-expect': validExpect,

package.json

@@ -25,7 +25,7 @@
  "eslint-plugin-prettier": "^2.3.1",
  "husky": "^0.14.3",
  "jest": "^21.2.1",
- "lint-staged": "^4.3.0",
+ "lint-staged": "^5.0.0",
  "prettier": "^1.8.1"
  },
  "prettier": {

rules/__tests__/prefer_to_be_null.test.js

@@ -0,0 +1,35 @@
+'use strict';
+
+const RuleTester = require('eslint').RuleTester;
+const rules = require('../../').rules;
+
+const ruleTester = new RuleTester();
+
+ruleTester.run('prefer_to_be_null', rules['prefer-to-be-null'], {
+ valid: ['expect(null).toBeNull();'],
+
+ invalid: [
+ {
+ code: 'expect(null).toBe(null);',
+ errors: [
+ {
+ message: 'Use toBeNull() instead',
+ column: 14,
+ line: 1,
+ },
+ ],
+ output: 'expect(null).toBeNull();',
+ },
+ {
+ code: 'expect(null).toEqual(null);',
+ errors: [
+ {
+ message: 'Use toBeNull() instead',
+ column: 14,
+ line: 1,
+ },
+ ],
+ output: 'expect(null).toBeNull();',
+ },
+ ],
+});

rules/prefer_to_be_null.js

@@ -0,0 +1,37 @@
+'use strict';
+
+module.exports = context => {
+ return {
+ CallExpression(node) {
+ const calleeName = node.callee.name;
+
+ if (
+ calleeName === 'expect' &&
+ node.arguments.length == 1 &&
+ node.parent &&
+ node.parent.type === 'MemberExpression' &&
+ node.parent.parent
+ ) {
+ const parentProperty = node.parent.property;
+ const propertyName = parentProperty.name;
+ const argument = node.parent.parent.arguments[0];
+
+ if (
+ (propertyName === 'toBe' || propertyName === 'toEqual') &&
+ argument.value === null
+ ) {
+ context.report({
+ fix(fixer) {
+ return [
+ fixer.replaceText(parentProperty, 'toBeNull'),
+ fixer.remove(argument),
+ ];
+ },
+ message: 'Use toBeNull() instead',
+ node: parentProperty,
+ });
+ }
+ }
+ },
+ };
+};