add tests

Author: xr0master

test/store/store_test.dart

@@ -0,0 +1,31 @@
+import 'package:emailjs/emailjs.dart';
+import 'package:emailjs/src/store/store.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:mocktail/mocktail.dart';
+
+class MockStorage extends Mock implements StorageProvider {}
+
+void main() {
+  test('origin setter', () {
+
+    final store = Store();
+    expect(store.host, 'api.emailjs.com');
+
+    store.origin = 'test.com';
+    expect(store.host, 'test.com');
+
+    store.origin = null;
+    expect(store.host, 'test.com');
+  });
+
+  test('storageProvider setter', () {
+
+    final store = Store();
+
+    store.storageProvider = MockStorage();
+    expect(store.storageProvider is MockStorage, true);
+
+    store.storageProvider = null;
+    expect(store.storageProvider is MockStorage, true);
+  });
+}