Finished Implementation of the google sign in provider and its tests, moved mock class definitions to the end of the file in all tests

test/src/resources/firestore_provider_test.dart

@@ -9,24 +9,6 @@ import 'package:do_more/src/resources/firestore_provider.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:mockito/mockito.dart';
 
-class MockFirestore extends Mock implements Firestore {}
-
-class MockCollectionReference extends Mock implements CollectionReference {}
-
-class MockDocumentReference extends Mock implements DocumentReference {}
-
-class MockDocumentSnapshot extends Mock implements DocumentSnapshot {
-  final Map<String, dynamic> data;
-
-  MockDocumentSnapshot([this.data]);
-
-  dynamic operator [](String key) => data[key];
-}
-
-class MockQuerySnapshot extends Mock implements QuerySnapshot {}
-
-class MockQuery extends Mock implements Query {}
-
 main() {
   final task = TaskModel(
     id: '1',
@@ -253,3 +235,21 @@ main() {
     });
   });
 }
+
+class MockFirestore extends Mock implements Firestore {}
+
+class MockCollectionReference extends Mock implements CollectionReference {}
+
+class MockDocumentReference extends Mock implements DocumentReference {}
+
+class MockDocumentSnapshot extends Mock implements DocumentSnapshot {
+  final Map<String, dynamic> data;
+
+  MockDocumentSnapshot([this.data]);
+
+  dynamic operator [](String key) => data[key];
+}
+
+class MockQuerySnapshot extends Mock implements QuerySnapshot {}
+
+class MockQuery extends Mock implements Query {}

test/src/resources/google_sign_in_provider_test.dart

@@ -0,0 +1,59 @@
+import 'dart:async';
+
+import 'package:do_more/src/resources/google_sign_in_provider.dart';
+import 'package:firebase_auth/firebase_auth.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:google_sign_in/google_sign_in.dart';
+import 'package:mockito/mockito.dart';
+
+main() {
+  group('GoogleSignInProvider', () {
+    test('should return an instance of user', () {
+      final googleSignIn = MockGoogleSignIn();
+      final auth = MockFirebaseAuth();
+      final googleUser = MockGoogleSignInAccount();
+      final googleAuth = MockGoogleSignInAuthentication();
+      final user = MockFirebaseUser();
+      final provider = GoogleSignInProvider(googleSignIn, auth);
+
+      when(googleSignIn.signIn()).thenAnswer((_) => Future.value(googleUser));
+      when(googleUser.authentication)
+          .thenAnswer((_) => Future.value(googleAuth));
+      when(auth.signInWithCredential(any))
+          .thenAnswer((_) => Future.value(user));
+
+      expect(provider.signIn(), completion(isInstanceOf<FirebaseUser>()));
+    });
+
+    test('should get the current user stored in cache', () {
+      final auth = MockFirebaseAuth();
+      final user = MockFirebaseUser();
+      final provider = GoogleSignInProvider(null, auth);
+
+      when(auth.currentUser()).thenAnswer((_) => Future.value(user));
+
+      expect(
+          provider.getCurrentUser(), completion(isInstanceOf<FirebaseUser>()));
+    });
+
+    test('should sign out a user', () {
+      final auth = MockFirebaseAuth();
+      final provider = GoogleSignInProvider(null, auth);
+
+      when(auth.signOut()).thenAnswer((_) => Future.value());
+
+      expect(provider.signOut(), completes);
+    });
+  });
+}
+
+class MockGoogleSignIn extends Mock implements GoogleSignIn {}
+
+class MockFirebaseAuth extends Mock implements FirebaseAuth {}
+
+class MockGoogleSignInAccount extends Mock implements GoogleSignInAccount {}
+
+class MockGoogleSignInAuthentication extends Mock
+    implements GoogleSignInAuthentication {}
+
+class MockFirebaseUser extends Mock implements FirebaseUser {}