fix: Better config mutation in rule tester

Author: scagood

__tests__/no-native.js

@@ -33,26 +33,26 @@ for (const ruleTester of ruleTesters) {
         code: 'Promise.resolve()',
         errors: [{ message: '"Promise" is not defined.' }],
       },
-      // {
-      //   code: 'new Promise(function(reject, resolve) { })',
-      //   errors: [{ message: '"Promise" is not defined.' }],
-      //   env: { browser: true },
-      // },
-      // {
-      //   code: 'new Promise(function(reject, resolve) { })',
-      //   errors: [{ message: '"Promise" is not defined.' }],
-      //   env: { node: true },
-      // },
-      // {
-      //   code: 'Promise.resolve()',
-      //   errors: [{ message: '"Promise" is not defined.' }],
-      //   env: { es6: true },
-      // },
-      // {
-      //   code: 'Promise.resolve()',
-      //   errors: [{ message: '"Promise" is not defined.' }],
-      //   globals: { Promise: true },
-      // },
+      {
+        code: 'new Promise(function(reject, resolve) { })',
+        errors: [{ message: '"Promise" is not defined.' }],
+        env: { browser: true },
+      },
+      {
+        code: 'new Promise(function(reject, resolve) { })',
+        errors: [{ message: '"Promise" is not defined.' }],
+        env: { node: true },
+      },
+      {
+        code: 'Promise.resolve()',
+        errors: [{ message: '"Promise" is not defined.' }],
+        env: { es6: true },
+      },
+      {
+        code: 'Promise.resolve()',
+        errors: [{ message: '"Promise" is not defined.' }],
+        globals: { Promise: true },
+      },
     ],
   })
 }

__tests__/rule-tester.js

@@ -5,30 +5,62 @@
 'use strict'
 const { version } = require('eslint/package.json')
 const { RuleTester } = require('eslint')
+const globals = require('globals')
 
 const majorVersion = Number.parseInt(version.split('.')[0], 10)
 
-exports.RuleTester = function (config = {}) {
-  if (majorVersion <= 8) {
-    return new RuleTester(config)
+function convertConfig(config) {
+  if (config instanceof Object === false) {
+    return config
   }
 
   if (config.languageOptions == null) {
     config.languageOptions = {}
   }
-  if (config.languageOptions.ecmaVersion == null) {
-    config.languageOptions.ecmaVersion = 2020
-  }
+
   if (config.parserOptions) {
     Object.assign(config.languageOptions, config.parserOptions)
   }
 
-  if (config.parser) {
+  if (typeof config.parser === 'string') {
     config.languageOptions.parser = require(config.parser)
   }
 
+  if (config.globals instanceof Object) {
+    config.languageOptions.globals = config.globals
+    delete config.globals
+  }
+
+  if (config.env instanceof Object) {
+    if (config.languageOptions.globals == null) {
+      config.languageOptions.globals = {}
+    }
+
+    for (const key in config.env) {
+      Object.assign(config.languageOptions.globals, globals[key])
+    }
+
+    delete config.env
+  }
+
   delete config.parserOptions
   delete config.parser
 
-  return new RuleTester(config)
+  return config
+}
+
+exports.RuleTester = function (config = {}) {
+  if (majorVersion <= 8) {
+    return new RuleTester(config)
+  }
+
+  const ruleTester = new RuleTester(convertConfig(config))
+  const $run = ruleTester.run.bind(ruleTester)
+  ruleTester.run = function (name, rule, tests) {
+    tests.valid = tests.valid.map(convertConfig)
+    tests.invalid = tests.invalid.map(convertConfig)
+
+    $run(name, rule, tests)
+  }
+  return ruleTester
 }

package-lock.json

@@ -75,6 +75,7 @@
     "eslint-plugin-jest": "^26.9.0",
     "eslint-plugin-node": "^11.1.0",
     "eslint-plugin-prettier": "^4.2.1",
+    "globals": "^14.0.0",
     "husky": "^7.0.4",
     "jest": "^28.1.3",
     "lint-staged": "^12.5.0",