diff --git a/test/domain/device_test.dart b/test/domain/device_test.dart
new file mode 100644
index 0000000..d2301be
--- /dev/null
+++ b/test/domain/device_test.dart
@@ -0,0 +1,22 @@
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:surf_widget_test_composer/domain/device.dart';
+
+void main() {
+  group('TestDevice', () {
+    test('should create TestDevice instance', () {
+      final device = TestDevice(
+        size: const Size(1080, 1920),
+        name: 'Test Device',
+        devicePixelRatio: 2.0,
+        safeArea: const EdgeInsets.all(10.0),
+      );
+
+      expect(device, isNotNull);
+      expect(device.name, equals('Test Device'));
+      expect(device.size, equals(const Size(1080, 1920)));
+      expect(device.devicePixelRatio, equals(2.0));
+      expect(device.safeArea, equals(const EdgeInsets.all(10.0)));
+    });
+  });
+}
diff --git a/test/unit_test.dart b/test/unit_test.dart
deleted file mode 100644
index 54467cc..0000000
--- a/test/unit_test.dart
+++ /dev/null
@@ -1,8 +0,0 @@
-import 'package:flutter_test/flutter_test.dart';
-
-void main() {
-  // Stub test.
-  test('should add two numbers together', () {
-    expect(1 + 1, 2);
-  });
-}