diff --git a/tests/astAnalyzer.test.ts b/tests/astAnalyzer.test.ts
new file mode 100644
index 0000000..856335f
--- /dev/null
+++ b/tests/astAnalyzer.test.ts
@@ -0,0 +1,64 @@
+import { describe, expect, it } from 'vitest';
+import { AstAnalyzer } from '../src/analyzer/astAnalyzer';
+
+describe('AstAnalyzer', () => {
+  it('should extract exported functions and their calls', () => {
+    const code = `
+import { db } from './db';
+
+export function getUser(userId: string) {
+  const user = db.user.findUnique(userId);
+  return user;
+}
+
+export const updateUser = (userId: string, data: any) => {
+  db.user.update(userId, data);
+};
+`;
+
+    const analysis = AstAnalyzer.analyzeFile('/test/auth.ts', code);
+    expect(analysis.symbols).toHaveLength(2);
+    expect(analysis.symbols[0].name).toBe('getUser');
+    expect(analysis.symbols[0].isExported).toBe(true);
+    expect(analysis.symbols[0].calls).toContain('findUnique');
+
+    expect(analysis.symbols[1].name).toBe('updateUser');
+    expect(analysis.symbols[1].kind).toBe('arrow_function');
+    expect(analysis.symbols[1].isExported).toBe(true);
+  });
+
+  it('should detect Next.js App Router API endpoints', () => {
+    const code = `
+export async function GET(request: Request) {
+  return Response.json({ ok: true });
+}
+
+export async function POST(request: Request) {
+  return Response.json({ created: true });
+}
+`;
+
+    const analysis = AstAnalyzer.analyzeFile('/app/api/orders/route.ts', code);
+    expect(analysis.hasApiRoute).toBe(true);
+    expect(analysis.apiRoutes).toHaveLength(2);
+    expect(analysis.apiRoutes[0].method).toBe('GET');
+    expect(analysis.apiRoutes[1].method).toBe('POST');
+  });
+
+  it('should find symbols intersecting with modified lines', () => {
+    const code = `
+export function first() {
+  return 1;
+}
+
+export function second() {
+  return 2;
+}
+`;
+    const analysis = AstAnalyzer.analyzeFile('/test/funcs.ts', code);
+    // line 2 is in 'first'
+    const touched = AstAnalyzer.findSymbolsAtLines(analysis.symbols, [3]);
+    expect(touched).toHaveLength(1);
+    expect(touched[0].name).toBe('first');
+  });
+});