test: use vitest as test runner for eslint-plugin-supa-mdx too

.github/workflows/test.yml

@@ -70,6 +70,6 @@ jobs:
       - name: js lint
         run: npm run lint
       - name: js tests
-        # Temporarily not running tests for eslint-plugin-supa-mdx until we
-        # figure out why the process never exits in CI only
+        # Temporarily ignore tests for eslint-plugin-supa-mdx until we figure
+        # out why the test runner never exits in CI only
         run: npm run test -w supa-mdx-lint

packages/eslint-supa-mdx/package.json

@@ -6,13 +6,14 @@
   "scripts": {
     "format": "prettier --write .",
     "format:check": "prettier --check .",
-    "test": "node tests/rule*.js",
+    "test": "vitest",
     "lint": "eslint ."
   },
   "devDependencies": {
     "@supa-mdx-lint/eslint-config": "*",
     "eslint": "^9.13.0",
-    "prettier": "^3.3.3"
+    "prettier": "^3.3.3",
+    "vitest": "^2.1.4"
   },
   "dependencies": {
     "supa-mdx-lint": "*",

packages/eslint-supa-mdx/tests/rule001_heading_case.test.js

@@ -0,0 +1,38 @@
+import { describe, expect, it } from "vitest";
+
+import { ruleTester } from "./utils.js";
+import rule001 from "../rules/rule001_heading_case.js";
+
+describe("Rule001HeadingCase", () => {
+  it("should enforce sentence case headings", () => {
+    const test = () => {
+      ruleTester.run("Rule001HeadingCase", rule001, {
+        valid: [
+          {
+            code: "# Sentence case heading",
+          },
+        ],
+        invalid: [
+          {
+            code: "# all lowercase heading",
+            errors: [
+              {
+                message: "Heading should be sentence case",
+              },
+            ],
+          },
+          {
+            code: "# Title Case Heading",
+            errors: [
+              {
+                message: "Heading should be sentence case",
+              },
+            ],
+          },
+        ],
+      });
+    };
+
+    expect(test).not.toThrow();
+  });
+});