added tests

frontend/src/lib/assert.test.ts

@@ -0,0 +1,26 @@
+import { describe, expect, test } from 'vitest';
+
+import { assert } from './assert';
+
+describe('assert', () => {
+  test('does not throw for true condition', () => {
+    expect(() => assert(true, 'should not throw')).not.toThrow();
+  });
+
+  test('throws in dev mode for false condition', () => {
+    expect(() => assert(false, 'should throw')).toThrow('Assertion failed: should throw');
+  });
+
+  test('includes message in error', () => {
+    try {
+      assert(false, 'custom message here');
+    } catch (e: any) {
+      expect(e.message).toContain('custom message here');
+    }
+  });
+
+  test('does not throw for truthy values', () => {
+    expect(() => assert(1 === 1, 'math works')).not.toThrow();
+    expect(() => assert('hello' === 'hello', 'strings work')).not.toThrow();
+  });
+});