diff --git a/src/util/assertUtil.spec.ts b/src/util/assertUtil.spec.ts
new file mode 100644
index 00000000..6e0b3c91
--- /dev/null
+++ b/src/util/assertUtil.spec.ts
@@ -0,0 +1,22 @@
+import { describe, it, expect } from 'vitest';
+import { assertDefined } from './assertUtil';
+
+// Example function tests
+describe('assertDefined', () => {
+  it.each([{}, 'test', 999, true, false, new Date()])(
+    'should not throw if value is defined: %s',
+    value => {
+      assertDefined(value, 'value');
+      expect(true).toBe(true);
+    }
+  );
+
+  it.each([null, undefined])(
+    'should throw an error for null or undefined values: %s',
+    value => {
+      expect(() => assertDefined(value, 'value')).toThrow(
+        `'value' is required`
+      );
+    }
+  );
+});