feat(core-eslint): usecase-must-have-test-file rule

packages/core-eslint/rules/usecase-must-have-test-file.test.js

@@ -0,0 +1,42 @@
+import { describe, it } from "vitest";
+import { RuleTester } from "eslint";
+import path from "node:path";
+import os from "node:os";
+import fs from "node:fs";
+import rule from "./usecase-must-have-test-file.js";
+
+function makeUseCaseFixture({ withTest }) {
+  const dir = fs.mkdtempSync(path.join(os.tmpdir(), "umht-"));
+  const useCase = path.join(dir, "sign-in.use-case.ts");
+  fs.writeFileSync(useCase, `export const signInUseCase = () => async () => {};`);
+  if (withTest) {
+    fs.writeFileSync(path.join(dir, "sign-in.use-case.test.ts"), `import { it } from "vitest"; it("works", () => {});`);
+  }
+  return { useCase };
+}
+
+const tester = new RuleTester({ languageOptions: { ecmaVersion: "latest", sourceType: "module" } });
+
+describe("usecase-must-have-test-file", () => {
+  it("passes when a sibling .test.ts exists", () => {
+    const { useCase } = makeUseCaseFixture({ withTest: true });
+    tester.run("usecase-must-have-test-file", rule, {
+      valid: [{ filename: useCase, code: fs.readFileSync(useCase, "utf8") }],
+      invalid: [],
+    });
+  });
+
+  it("fires when no sibling test file exists", () => {
+    const { useCase } = makeUseCaseFixture({ withTest: false });
+    tester.run("usecase-must-have-test-file", rule, {
+      valid: [],
+      invalid: [
+        {
+          filename: useCase,
+          code: fs.readFileSync(useCase, "utf8"),
+          errors: [{ messageId: "missingTestFile" }],
+        },
+      ],
+    });
+  });
+});