feat: create new prefer-mock-return-shorthand rule (#1897)

Author: G-Rath

README.md

@@ -374,6 +374,7 @@ Manually fixable by
 | [prefer-jest-mocked](docs/rules/prefer-jest-mocked.md)                               | Prefer `jest.mocked()` over `fn as jest.Mock`                             |     |     | 🔧  |     |
 | [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-mock-return-shorthand](docs/rules/prefer-mock-return-shorthand.md)           | Prefer mock return shorthands                                             |     |     | 🔧  |     |
 | [prefer-snapshot-hint](docs/rules/prefer-snapshot-hint.md)                           | Prefer including a hint with external snapshots                           |     |     |     |     |
 | [prefer-spy-on](docs/rules/prefer-spy-on.md)                                         | Suggest using `jest.spyOn()`                                              |     |     | 🔧  |     |
 | [prefer-strict-equal](docs/rules/prefer-strict-equal.md)                             | Suggest using `toStrictEqual()`                                           |     |     |     | 💡  |

docs/rules/prefer-mock-return-shorthand.md

@@ -0,0 +1,48 @@
+# Prefer mock return shorthands (`prefer-mock-return-shorthand`)
+
+🔧 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 -->
+
+When working with mocks of functions that return simple values, Jest provides
+some API sugar functions to reduce the amount of boilerplate you have to write.
+
+These methods should be preferred when possible.
+
+## Rule details
+
+The following patterns are warnings:
+
+```js
+jest.fn().mockImplementation(() => 'hello world');
+
+jest
+  .spyOn(fs.promises, 'readFile')
+  .mockImplementationOnce(() => Promise.reject(new Error('oh noes!')));
+
+myFunction
+  .mockImplementationOnce(() => 42)
+  .mockImplementationOnce(() => Promise.resolve(42))
+  .mockReturnValue(0);
+```
+
+The following patterns are not warnings:
+
+```js
+jest.fn().mockResolvedValue(123);
+
+jest
+  .spyOn(fs.promises, 'readFile')
+  .mockReturnValue(Promise.reject(new Error('oh noes!')));
+jest.spyOn(fs.promises, 'readFile').mockRejectedValue(new Error('oh noes!'));
+
+jest.spyOn(fs, 'readFileSync').mockImplementationOnce(() => {
+  throw new Error('oh noes!');
+});
+
+myFunction
+  .mockResolvedValueOnce(42)
+  .mockResolvedValueOnce(42)
+  .mockReturnValue(0);
+```

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

@@ -61,6 +61,7 @@ exports[`rules should export configs that refer to actual rules 1`] = `
       "jest/prefer-jest-mocked": "error",
       "jest/prefer-lowercase-title": "error",
       "jest/prefer-mock-promise-shorthand": "error",
+      "jest/prefer-mock-return-shorthand": "error",
       "jest/prefer-snapshot-hint": "error",
       "jest/prefer-spy-on": "error",
       "jest/prefer-strict-equal": "error",
@@ -160,6 +161,7 @@ exports[`rules should export configs that refer to actual rules 1`] = `
       "jest/prefer-jest-mocked": "error",
       "jest/prefer-lowercase-title": "error",
       "jest/prefer-mock-promise-shorthand": "error",
+      "jest/prefer-mock-return-shorthand": "error",
       "jest/prefer-snapshot-hint": "error",
       "jest/prefer-spy-on": "error",
       "jest/prefer-strict-equal": "error",

src/__tests__/rules.test.ts

@@ -2,7 +2,7 @@ import { existsSync } from 'fs';
 import { resolve } from 'path';
 import plugin from '../';
 
-const numberOfRules = 70;
+const numberOfRules = 71;
 const ruleNames = Object.keys(plugin.rules);
 const deprecatedRules = Object.entries(plugin.rules)
   .filter(([, rule]) => rule.meta.deprecated)