feat(linter/plugins): introduce RuleTester

Author: overlookmotel

apps/oxlint/package.json

@@ -22,13 +22,15 @@
   "devDependencies": {
     "@types/esquery": "^1.5.4",
     "@types/estree": "^1.0.8",
+    "@types/json-stable-stringify-without-jsonify": "^1.0.2",
     "@typescript-eslint/scope-manager": "8.46.2",
     "@typescript-eslint/typescript-estree": "^8.47.0",
     "cross-env": "catalog:",
     "eslint": "^9.36.0",
     "esquery": "^1.6.0",
     "execa": "^9.6.0",
     "jiti": "^2.6.0",
+    "json-stable-stringify-without-jsonify": "^1.0.1",
     "oxc-parser": "^0.99.0",
     "rolldown": "catalog:",
     "tsdown": "catalog:",

apps/oxlint/src-js/index.ts

@@ -1,6 +1,11 @@
+// Functions and classes
 export { definePlugin, defineRule } from "./package/define.js";
+export { RuleTester } from "./package/rule_tester.js";
 
+// ESTree types
 export type * as ESTree from "./generated/types.d.ts";
+
+// Plugin types
 export type { Context, LanguageOptions } from "./plugins/context.ts";
 export type { Fix, Fixer, FixFn } from "./plugins/fix.ts";
 export type { CreateOnceRule, CreateRule, Plugin, Rule } from "./plugins/load.ts";
@@ -57,3 +62,23 @@ export type {
   Visitor,
   VisitorWithHooks,
 } from "./plugins/types.ts";
+
+// Rule tester types.
+// Export as namespace to avoid lengthy type names.
+import type {
+  Config as _Config,
+  DescribeFn as _DescribeFn,
+  ItFn as _ItFn,
+  ValidTestCase as _ValidTestCase,
+  InvalidTestCase as _InvalidTestCase,
+  TestCases as _TestCases,
+} from "./package/rule_tester.ts";
+
+export namespace RuleTester {
+  export type Config = _Config;
+  export type DescribeFn = _DescribeFn;
+  export type ItFn = _ItFn;
+  export type ValidTestCase = _ValidTestCase;
+  export type InvalidTestCase = _InvalidTestCase;
+  export type TestCases = _TestCases;
+}