Repository: eslint/eslint
File: lib/rule-tester/rule-tester.js (JavaScript)

Code before:
const { defaultConfig } = require("../config/default-config");

const ajv = require("../shared/ajv")({ strictDefaults: true });

const parserSymbol = Symbol.for("eslint.RuleTester.parser");
const { ConfigArraySymbol } = require("@eslint/config-array");
const { isSerializable } = require("../shared/serialization");

const { SourceCode } = require("../languages/js/source-code");

//------------------------------------------------------------------------------
// Typedefs
//------------------------------------------------------------------------------

/** @typedef {import("../shared/types").Parser} Parser */
/** @typedef {import("../shared/types").LanguageOptions} LanguageOptions */
/** @typedef {import("../shared/types").Rule} Rule */


/**
 * A test case that is expected to pass lint.
 * @typedef {Object} ValidTestCase
 * @property {string} [name] Name for the test case.
 * @property {string} code Code for the test case.
 * @property {any[]} [options] Options for the test case.
 * @property {Function} [setup] Function to execute before testing the case.
 * @property {LanguageOptions} [languageOptions] The language options to use in the test case.
 * @property {{ [name: string]: any }} [settings] Settings for the test case.
 * @property {string} [filename] The fake filename for the test case. Useful for rules that make assertion about filenames.
 * @property {boolean} [only] Run only this test case or the subset of test cases with this property.
 */

/**
 * A test case that is expected to fail lint.
 * @typedef {Object} InvalidTestCase
 * @property {string} [name] Name for the test case.
 * @property {string} code Code for the test case.
 * @property {number | Array<TestCaseError | string | RegExp>} errors Expected errors.
 * @property {string | null} [output] The expected code after autofixes are applied. If set to `null`, the test runner will assert that no autofix is suggested.
 * @property {any[]} [options] Options for the test case.
 * @property {Function} [setup] Function to execute before testing the case.
 * @property {{ [name: string]: any }} [settings] Settings for the test case.
 * @property {string} [filename] The fake filename for the test case. Useful for rules that make assertion about filenames.
 * @property {LanguageOptions} [languageOptions] The language options to use in the test case.
 * @property {boolean} [only] Run only this test case or the subset of test cases with this property.
 */

/**
 * A description of a reported error used in a rule tester test.
 * @typedef {Object} TestCaseError
 * @property {string | RegExp} [message] Message.

Review comment (suggestion):
```suggestion
 * @property {Function} [before] Function to execute before testing the case.
```

Code after:
const { defaultConfig } = require("../config/default-config");

const ajv = require("../shared/ajv")({ strictDefaults: true });

const parserSymbol = Symbol.for("eslint.RuleTester.parser");
const { ConfigArraySymbol } = require("@eslint/config-array");
const { isSerializable } = require("../shared/serialization");

const { SourceCode } = require("../languages/js/source-code");

//------------------------------------------------------------------------------
// Typedefs
//------------------------------------------------------------------------------

/** @typedef {import("../shared/types").Parser} Parser */
/** @typedef {import("../shared/types").LanguageOptions} LanguageOptions */
/** @typedef {import("../shared/types").Rule} Rule */


/**
 * A test case that is expected to pass lint.
 * @typedef {Object} ValidTestCase
 * @property {string} [name] Name for the test case.
 * @property {string} code Code for the test case.
 * @property {any[]} [options] Options for the test case.
 * @property {Function} [before] Function to execute before testing the case.
 * @property {Function} [after] Function to execute after testing the case regardless of its result.
 * @property {LanguageOptions} [languageOptions] The language options to use in the test case.
 * @property {{ [name: string]: any }} [settings] Settings for the test case.
 * @property {string} [filename] The fake filename for the test case. Useful for rules that make assertion about filenames.
 * @property {boolean} [only] Run only this test case or the subset of test cases with this property.
 */

/**
 * A test case that is expected to fail lint.
 * @typedef {Object} InvalidTestCase
 * @property {string} [name] Name for the test case.
 * @property {string} code Code for the test case.
 * @property {number | Array<TestCaseError | string | RegExp>} errors Expected errors.
 * @property {string | null} [output] The expected code after autofixes are applied. If set to `null`, the test runner will assert that no autofix is suggested.
 * @property {any[]} [options] Options for the test case.
 * @property {Function} [before] Function to execute before testing the case.
 * @property {Function} [after] Function to execute after testing the case regardless of its result.
 * @property {{ [name: string]: any }} [settings] Settings for the test case.
 * @property {string} [filename] The fake filename for the test case. Useful for rules that make assertion about filenames.
 * @property {LanguageOptions} [languageOptions] The language options to use in the test case.
 * @property {boolean} [only] Run only this test case or the subset of test cases with this property.
 */

/**
 * A description of a reported error used in a rule tester test.