feat: prefer importing jest globals [new rule]

- Fix #1101

Issue: #1101

README.md

@@ -248,6 +248,7 @@ set to warn in.\
 | [prefer-expect-resolves](docs/rules/prefer-expect-resolves.md)               | Prefer `await expect(...).resolves` over `expect(await ...)` syntax       |     |     | 🔧  |     |     |
 | [prefer-hooks-in-order](docs/rules/prefer-hooks-in-order.md)                 | Prefer having hooks in a consistent order                                 |     |     |     |     |     |
 | [prefer-hooks-on-top](docs/rules/prefer-hooks-on-top.md)                     | Suggest having hooks before any test cases                                |     |     |     |     |     |
+| [prefer-jest-globals](docs/rules/prefer-jest-globals.md)                     | Prefer importing Jest globals                                             |     |     | 🔧  |     |     |
 | [prefer-lowercase-title](docs/rules/prefer-lowercase-title.md)               | Enforce lowercase test names                                              |     |     | 🔧  |     |     |
 | [prefer-mock-promise-shorthand](docs/rules/prefer-mock-promise-shorthand.md) | Prefer mock resolved/rejected shorthands for promises                     |     |     | 🔧  |     |     |
 | [prefer-snapshot-hint](docs/rules/prefer-snapshot-hint.md)                   | Prefer including a hint with external snapshots                           |     |     |     |     |     |

docs/rules/prefer-jest-globals.md

@@ -0,0 +1,47 @@
+# Prefer importing Jest globals (`prefer-jest-globals`)
+
+🔧 This rule is automatically fixable by the
+[`--fix` CLI option](https://eslint.org/docs/latest/user-guide/command-line-interface#--fix).
+
+<!-- end auto-generated rule header -->
+
+This rule aims to enforce explicit imports from `@jest/globals`.
+
+1. This is useful for ensuring that the Jest APIs are imported the same way in
+   the codebase.
+2. When you can't modify Jest's
+   [`injectGlobals`](https://jestjs.io/docs/configuration#injectglobals-boolean)
+   configuration property, this rule can help to ensure that the Jest globals
+   are imported explicitly and facilitate a migration to `@jest/globals`.
+
+## Rule details
+
+Examples of **incorrect** code for this rule
+
+```js
+/* eslint jest/prefer-jest-globals: "error" */
+
+describe('foo', () => {
+  it('accepts this input', () => {
+    // ...
+  });
+});
+```
+
+Examples of **correct** code for this rule
+
+```js
+/* eslint jest/prefer-jest-globals: "error" */
+
+import { describe, it } from '@jest/globals';
+
+describe('foo', () => {
+  it('accepts this input', () => {
+    // ...
+  });
+});
+```
+
+## Further Reading
+
+- [Documentation](https://jestjs.io/docs/api)

src/__tests__/__snapshots__/rules.test.ts.snap

@@ -45,6 +45,7 @@ exports[`rules should export configs that refer to actual rules 1`] = `
       "jest/prefer-expect-resolves": "error",
       "jest/prefer-hooks-in-order": "error",
       "jest/prefer-hooks-on-top": "error",
+      "jest/prefer-jest-globals": "error",
       "jest/prefer-lowercase-title": "error",
       "jest/prefer-mock-promise-shorthand": "error",
       "jest/prefer-snapshot-hint": "error",

src/__tests__/rules.test.ts

@@ -2,7 +2,7 @@ import { existsSync } from 'fs';
 import { resolve } from 'path';
 import plugin from '../';
 
-const numberOfRules = 53;
+const numberOfRules = 54;
 const ruleNames = Object.keys(plugin.rules);
 const deprecatedRules = Object.entries(plugin.rules)
   .filter(([, rule]) => rule.meta.deprecated)

src/rules/__tests__/prefer-jest-globals.test.ts

@@ -0,0 +1,36 @@
+import { TSESLint } from '@typescript-eslint/utils';
+import dedent from 'dedent';
+import rule from '../prefer-jest-globals';
+import { espreeParser } from './test-utils';
+
+const ruleTester = new TSESLint.RuleTester({
+  parser: espreeParser,
+  parserOptions: {
+    ecmaVersion: 2015,
+    sourceType: 'module',
+  },
+});
+
+ruleTester.run('prefer-jest-globals.test', rule, {
+  valid: [
+    {
+      code: dedent`
+        import { test, expect } from '@jest/globals';
+
+        test('should pass', () => {
+            expect(true).toBeDefined();
+        });
+        `,
+      parserOptions: { sourceType: 'module' },
+    },
+  ],
+  invalid: [
+    {
+      code: dedent`
+        it("foo");
+      `,
+      parserOptions: { sourceType: 'module' },
+      errors: [{ endColumn: 11, column: 1, messageId: 'preferJestGlobal' }],
+    },
+  ],
+});

src/rules/prefer-jest-globals.ts

@@ -0,0 +1,60 @@
+import globalsJson from '../globals.json';
+import { createRule } from './utils';
+
+export default createRule({
+  name: __filename,
+  meta: {
+    docs: {
+      category: 'Best Practices',
+      description: 'Prefer importing Jest globals',
+      recommended: false,
+    },
+    messages: {
+      preferJestGlobal:
+        "Jest function \"{{ jestFunction }} is used but not imported from '@jest/globals'",
+    },
+    fixable: 'code',
+    type: 'suggestion',
+    schema: [],
+  },
+  defaultOptions: [],
+  create(context) {
+    const jestFunctions = Object.keys(globalsJson);
+    const importedJestFunctions: any[] = [];
+    const usedJestFunctions = new Set();
+
+    return {
+      ImportDeclaration(node) {
+        // Check if the import source is '@jest/globals'
+        /* istanbul ignore else */
+        if (node.source.value === '@jest/globals') {
+          node.specifiers.forEach(specifier => {
+            /* istanbul ignore else */
+            if (
+              specifier.type === 'ImportSpecifier' &&
+              jestFunctions.includes(specifier.imported.name)
+            ) {
+              importedJestFunctions.push(specifier.imported.name);
+            }
+          });
+        }
+      },
+      Identifier(node) {
+        if (jestFunctions.includes(node.name)) {
+          usedJestFunctions.add(node.name);
+        }
+      },
+      'Program:exit'() {
+        usedJestFunctions.forEach(jestFunction => {
+          if (!importedJestFunctions.includes(jestFunction)) {
+            context.report({
+              node: context.getSourceCode().ast,
+              messageId: 'preferJestGlobal',
+              data: { jestFunction },
+            });
+          }
+        });
+      },
+    };
+  },
+});