diff --git a/tests/testRunner.test.ts b/tests/testRunner.test.ts
new file mode 100644
index 0000000..dd7538f
--- /dev/null
+++ b/tests/testRunner.test.ts
@@ -0,0 +1,40 @@
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import * as path from 'node:path';
+import { afterEach, beforeEach, describe, expect, it } from 'vitest';
+import { TestRunner } from '../src/test-runner/testRunner';
+
+describe('TestRunner', () => {
+  let tempDir: string;
+
+  beforeEach(() => {
+    tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'proofcode-runner-test-'));
+  });
+
+  afterEach(() => {
+    fs.rmSync(tempDir, { recursive: true, force: true });
+  });
+
+  it('should detect pnpm, yarn, bun, and npm based on lockfiles', () => {
+    const runner = new TestRunner();
+
+    expect(runner.detectPackageManager(tempDir)).toBe('npm');
+
+    fs.writeFileSync(path.join(tempDir, 'pnpm-lock.yaml'), '');
+    expect(runner.detectPackageManager(tempDir)).toBe('pnpm');
+
+    fs.unlinkSync(path.join(tempDir, 'pnpm-lock.yaml'));
+    fs.writeFileSync(path.join(tempDir, 'yarn.lock'), '');
+    expect(runner.detectPackageManager(tempDir)).toBe('yarn');
+
+    fs.unlinkSync(path.join(tempDir, 'yarn.lock'));
+    fs.writeFileSync(path.join(tempDir, 'bun.lockb'), '');
+    expect(runner.detectPackageManager(tempDir)).toBe('bun');
+  });
+
+  it('should skip TypeScript check if no tsconfig.json exists', async () => {
+    const runner = new TestRunner();
+    const result = await runner.runTypeScriptCheck(tempDir);
+    expect(result.status).toBe('SKIPPED');
+  });
+});