typescript-eslint · bradzacher · Apr 28, 2023 · Apr 1, 2023 · Apr 27, 2023 · Apr 27, 2023
diff --git a/packages/eslint-plugin-internal/package.json b/packages/eslint-plugin-internal/package.json
@@ -14,6 +14,7 @@
   },
   "dependencies": {
     "@types/prettier": "*",
+    "@typescript-eslint/rule-tester": "5.59.1",
     "@typescript-eslint/scope-manager": "5.59.1",
     "@typescript-eslint/type-utils": "5.59.1",
     "@typescript-eslint/utils": "5.59.1",

diff --git a/packages/eslint-plugin-internal/tests/RuleTester.ts b/packages/eslint-plugin-internal/tests/RuleTester.ts
@@ -1,10 +1,8 @@
-import { ESLintUtils } from '@typescript-eslint/utils';
 import path from 'path';
 
 function getFixturesRootDir(): string {
   return path.join(__dirname, 'fixtures');
 }
 
-const { batchedSingleLineTests, RuleTester } = ESLintUtils;
-
-export { RuleTester, batchedSingleLineTests, getFixturesRootDir };
+export { RuleTester } from '@typescript-eslint/rule-tester';
+export { getFixturesRootDir };
diff --git a/packages/eslint-plugin-internal/tests/rules/no-poorly-typed-ts-props.test.ts b/packages/eslint-plugin-internal/tests/rules/no-poorly-typed-ts-props.test.ts
@@ -1,6 +1,8 @@
 /* eslint-disable @typescript-eslint/internal/prefer-ast-types-enum */
+import { RuleTester } from '@typescript-eslint/rule-tester';
+
 import rule from '../../src/rules/no-poorly-typed-ts-props';
-import { getFixturesRootDir, RuleTester } from '../RuleTester';
+import { getFixturesRootDir } from '../RuleTester';
 
 const ruleTester = new RuleTester({
   parser: '@typescript-eslint/parser',

diff --git a/packages/eslint-plugin-internal/tests/rules/no-typescript-default-import.test.ts b/packages/eslint-plugin-internal/tests/rules/no-typescript-default-import.test.ts
@@ -1,5 +1,6 @@
+import { RuleTester } from '@typescript-eslint/rule-tester';
+
 import rule from '../../src/rules/no-typescript-default-import';
-import { batchedSingleLineTests, RuleTester } from '../RuleTester';
 
 const ruleTester = new RuleTester({
   parser: '@typescript-eslint/parser',
@@ -16,30 +17,21 @@ ruleTester.run('no-typescript-default-import', rule, {
     'import ts = foo;',
     "import ts = require('nottypescript');",
   ],
-  invalid: batchedSingleLineTests({
-    code: `
-import ts from 'typescript';
-import ts, { SyntaxKind } from 'typescript';
-import ts = require('typescript');
-    `,
-    output: `
-import * as ts from 'typescript';
-import ts, { SyntaxKind } from 'typescript';
-import * as ts from 'typescript';
-    `,
-    errors: [
-      {
-        messageId: 'noTSDefaultImport',
-        line: 2,
-      },
-      {
-        messageId: 'noTSDefaultImport',
-        line: 3,
-      },
-      {
-        messageId: 'noTSDefaultImport',
-        line: 4,
-      },
-    ],
-  }),
+  invalid: [
+    {
+      code: "import ts from 'typescript';",
+      output: `import * as ts from 'typescript';`,
+      errors: [{ messageId: 'noTSDefaultImport' }],
+    },
+    {
+      code: "import ts, { SyntaxKind } from 'typescript';",
+      output: null,
+      errors: [{ messageId: 'noTSDefaultImport' }],
+    },
+    {
+      code: "import ts = require('typescript');",
+      output: `import * as ts from 'typescript';`,
+      errors: [{ messageId: 'noTSDefaultImport' }],
+    },
+  ],
 });
diff --git a/packages/eslint-plugin-internal/tests/rules/no-typescript-estree.test.ts b/packages/eslint-plugin-internal/tests/rules/no-typescript-estree.test.ts
@@ -1,5 +1,6 @@
+import { RuleTester } from '@typescript-eslint/rule-tester';
+
 import rule from '../../src/rules/no-typescript-estree-import';
-import { batchedSingleLineTests, RuleTester } from '../RuleTester';
 
 const ruleTester = new RuleTester({
   parser: '@typescript-eslint/parser',
@@ -14,48 +15,36 @@ ruleTester.run('no-typescript-estree-import', rule, {
     "import foo from '@typescript-eslint/utils';",
     "import * as foo from '@typescript-eslint/utils';",
   ],
-  invalid: batchedSingleLineTests({
-    code: `
-import { foo } from '@typescript-eslint/typescript-estree';
-import foo from '@typescript-eslint/typescript-estree';
-import * as foo from '@typescript-eslint/typescript-estree';
-import { foo } from '@typescript-eslint/types';
-import foo from '@typescript-eslint/types';
-import * as foo from '@typescript-eslint/types';
-    `,
-    output: `
-import { foo } from '@typescript-eslint/utils';
-import foo from '@typescript-eslint/utils';
-import * as foo from '@typescript-eslint/utils';
-import { foo } from '@typescript-eslint/utils';
-import foo from '@typescript-eslint/utils';
-import * as foo from '@typescript-eslint/utils';
-    `,
-    errors: [
-      {
-        messageId: 'dontImportPackage',
-        line: 2,
-      },
-      {
-        messageId: 'dontImportPackage',
-        line: 3,
-      },
-      {
-        messageId: 'dontImportPackage',
-        line: 4,
-      },
-      {
-        messageId: 'dontImportPackage',
-        line: 5,
-      },
-      {
-        messageId: 'dontImportPackage',
-        line: 6,
-      },
-      {
-        messageId: 'dontImportPackage',
-        line: 7,
-      },
-    ],
-  }),
+  invalid: [
+    {
+      code: "import { foo } from '@typescript-eslint/typescript-estree';",
+      output: "import { foo } from '@typescript-eslint/utils';",
+      errors: [{ messageId: 'dontImportPackage' }],
+    },
+    {
+      code: "import foo from '@typescript-eslint/typescript-estree';",
+      output: "import foo from '@typescript-eslint/utils';",
+      errors: [{ messageId: 'dontImportPackage' }],
+    },
+    {
+      code: "import * as foo from '@typescript-eslint/typescript-estree';",
+      output: "import * as foo from '@typescript-eslint/utils';",
+      errors: [{ messageId: 'dontImportPackage' }],
+    },
+    {
+      code: "import { foo } from '@typescript-eslint/types';",
+      output: "import { foo } from '@typescript-eslint/utils';",
+      errors: [{ messageId: 'dontImportPackage' }],
+    },
+    {
+      code: "import foo from '@typescript-eslint/types';",
+      output: "import foo from '@typescript-eslint/utils';",
+      errors: [{ messageId: 'dontImportPackage' }],
+    },
+    {
+      code: "import * as foo from '@typescript-eslint/types';",
+      output: "import * as foo from '@typescript-eslint/utils';",
+      errors: [{ messageId: 'dontImportPackage' }],
+    },
+  ],
 });
diff --git a/packages/eslint-plugin-internal/tests/rules/plugin-test-formatting.test.ts b/packages/eslint-plugin-internal/tests/rules/plugin-test-formatting.test.ts
@@ -1,5 +1,7 @@
+import { RuleTester } from '@typescript-eslint/rule-tester';
+
 import rule from '../../src/rules/plugin-test-formatting';
-import { getFixturesRootDir, RuleTester } from '../RuleTester';
+import { getFixturesRootDir } from '../RuleTester';
 
 const ruleTester = new RuleTester({
   parser: '@typescript-eslint/parser',

diff --git a/packages/eslint-plugin-internal/tests/rules/prefer-ast-types-enum.test.ts b/packages/eslint-plugin-internal/tests/rules/prefer-ast-types-enum.test.ts
@@ -1,8 +1,8 @@
+import { RuleTester } from '@typescript-eslint/rule-tester';
 import { DefinitionType } from '@typescript-eslint/scope-manager';
 import { AST_NODE_TYPES, AST_TOKEN_TYPES } from '@typescript-eslint/utils';
 
 import rule from '../../src/rules/prefer-ast-types-enum';
-import { batchedSingleLineTests, RuleTester } from '../RuleTester';
 
 const ruleTester = new RuleTester({
   parser: '@typescript-eslint/parser',
@@ -29,33 +29,42 @@ ruleTester.run('prefer-ast-types-enum', rule, {
       }
     `,
   ],
-  invalid: batchedSingleLineTests({
-    code: `
-node.type === 'Literal';
-node.type === 'Keyword';
-node.type === 'Parameter';
-    `,
-    output: `
-node.type === AST_NODE_TYPES.Literal;
-node.type === AST_TOKEN_TYPES.Keyword;
-node.type === DefinitionType.Parameter;
-    `,
-    errors: [
-      {
-        data: { enumName: 'AST_NODE_TYPES', literal: AST_NODE_TYPES.Literal },
-        messageId: 'preferEnum',
-        line: 2,
-      },
-      {
-        data: { enumName: 'AST_TOKEN_TYPES', literal: AST_TOKEN_TYPES.Keyword },
-        messageId: 'preferEnum',
-        line: 3,
-      },
-      {
-        data: { enumName: 'DefinitionType', literal: DefinitionType.Parameter },
-        messageId: 'preferEnum',
-        line: 4,
-      },
-    ],
-  }),
+  invalid: [
+    {
+      code: "node.type === 'Literal';",
+      output: 'node.type === AST_NODE_TYPES.Literal;',
+      errors: [
+        {
+          data: { enumName: 'AST_NODE_TYPES', literal: AST_NODE_TYPES.Literal },
+          messageId: 'preferEnum',
+        },
+      ],
+    },
+    {
+      code: "node.type === 'Keyword';",
+      output: 'node.type === AST_TOKEN_TYPES.Keyword;',
+      errors: [
+        {
+          data: {
+            enumName: 'AST_TOKEN_TYPES',
+            literal: AST_TOKEN_TYPES.Keyword,
+          },
+          messageId: 'preferEnum',
+        },
+      ],
+    },
+    {
+      code: "node.type === 'Parameter';",
+      output: 'node.type === DefinitionType.Parameter;',
+      errors: [
+        {
+          data: {
+            enumName: 'DefinitionType',
+            literal: DefinitionType.Parameter,
+          },
+          messageId: 'preferEnum',
+        },
+      ],
+    },
+  ],
 });
diff --git a/packages/eslint-plugin/package.json b/packages/eslint-plugin/package.json
@@ -72,6 +72,7 @@
     "@types/natural-compare": "*",
     "@types/prettier": "*",
     "@typescript-eslint/rule-schema-to-typescript-types": "5.59.1",
+    "@typescript-eslint/rule-tester": "5.59.1",
     "cross-fetch": "*",
     "jest-specific-snapshot": "*",
     "json-schema": "*",

diff --git a/packages/eslint-plugin/src/rules/consistent-type-assertions.ts b/packages/eslint-plugin/src/rules/consistent-type-assertions.ts
@@ -4,7 +4,7 @@ import { AST_NODE_TYPES } from '@typescript-eslint/utils';
 import * as util from '../util';
 
 // intentionally mirroring the options
-type MessageIds =
+export type MessageIds =
   | 'as'
   | 'angle-bracket'
   | 'never'
@@ -19,7 +19,7 @@ type OptUnion =
   | {
       assertionStyle: 'never';
     };
-type Options = [OptUnion];
+export type Options = readonly [OptUnion];
 
 export default util.createRule<Options, MessageIds>({
   name: 'consistent-type-assertions',

diff --git a/packages/eslint-plugin/tests/RuleTester.ts b/packages/eslint-plugin/tests/RuleTester.ts
@@ -1,17 +1,80 @@
-import { ESLintUtils } from '@typescript-eslint/utils';
+import type {
+  InvalidTestCase,
+  ValidTestCase,
+} from '@typescript-eslint/rule-tester';
 import * as path from 'path';
 
-function getFixturesRootDir(): string {
+export function getFixturesRootDir(): string {
   return path.join(__dirname, 'fixtures');
 }
 
-const { batchedSingleLineTests } = ESLintUtils;
-export {
-  RuleTester,
-  RunTests,
-  ValidTestCase,
-  InvalidTestCase,
-  noFormat,
-} from '@typescript-eslint/utils/eslint-utils/rule-tester';
-
-export { batchedSingleLineTests, getFixturesRootDir };
+/**
+ * Converts a batch of single line tests into a number of separate test cases.
+ * This makes it easier to write tests which use the same options.
+ *
+ * Why wouldn't you just leave them as one test?
+ * Because it makes the test error messages harder to decipher.
+ * This way each line will fail separately, instead of them all failing together.
+ *
+ * @deprecated - DO NOT USE THIS FOR NEW RULES
+ */
+export function batchedSingleLineTests<TOptions extends readonly unknown[]>(
+  test: ValidTestCase<TOptions>,
+): ValidTestCase<TOptions>[];
+/**
+ * Converts a batch of single line tests into a number of separate test cases.
+ * This makes it easier to write tests which use the same options.
+ *
+ * Why wouldn't you just leave them as one test?
+ * Because it makes the test error messages harder to decipher.
+ * This way each line will fail separately, instead of them all failing together.
+ *
+ * Make sure you have your line numbers correct for error reporting, as it will match
+ * the line numbers up with the split tests!
+ *
+ * @deprecated - DO NOT USE THIS FOR NEW RULES
+ */
+export function batchedSingleLineTests<
+  TMessageIds extends string,
+  TOptions extends readonly unknown[],
+>(
+  test: InvalidTestCase<TMessageIds, TOptions>,
+): InvalidTestCase<TMessageIds, TOptions>[];
+export function batchedSingleLineTests<
+  TMessageIds extends string,
+  TOptions extends readonly unknown[],
+>(
+  options: ValidTestCase<TOptions> | InvalidTestCase<TMessageIds, TOptions>,
+): (ValidTestCase<TOptions> | InvalidTestCase<TMessageIds, TOptions>)[] {
+  // -- eslint counts lines from 1
+  const lineOffset = options.code.startsWith('\n') ? 2 : 1;
+  const output =
+    'output' in options && options.output
+      ? options.output.trim().split('\n')
+      : null;
+  return options.code
+    .trim()
+    .split('\n')
+    .map((code, i) => {
+      const lineNum = i + lineOffset;
+      const errors =
+        'errors' in options
+          ? options.errors.filter(e => e.line === lineNum)
+          : [];
+      const returnVal = {
+        ...options,
+        code,
+        errors: errors.map(e => ({
+          ...e,
+          line: 1,
+        })),
+      };
+      if (output?.[i]) {
+        return {
+          ...returnVal,
+          output: output[i],
+        };
+      }
+      return returnVal;
+    });
+}
diff --git a/packages/eslint-plugin/tests/eslint-rules/arrow-parens.test.ts b/packages/eslint-plugin/tests/eslint-rules/arrow-parens.test.ts
@@ -1,5 +1,6 @@
+import { noFormat, RuleTester } from '@typescript-eslint/rule-tester';
+
 import { getESLintCoreRule } from '../../src/util/getESLintCoreRule';
-import { noFormat, RuleTester } from '../RuleTester';
 
 const rule = getESLintCoreRule('arrow-parens');