diff --git a/StoredCredentialForTesting b/StoredCredentialForTesting
new file mode 100644
index 000000000000..cef2ff6b3bee
Binary files /dev/null and b/StoredCredentialForTesting differ
diff --git a/src/test/java/seedu/agendum/sync/SyncProviderGoogleTests.java b/src/test/java/seedu/agendum/sync/SyncProviderGoogleTests.java
index c110c344e9e7..0bf0265272eb 100644
--- a/src/test/java/seedu/agendum/sync/SyncProviderGoogleTests.java
+++ b/src/test/java/seedu/agendum/sync/SyncProviderGoogleTests.java
@@ -1,28 +1,77 @@
 package seedu.agendum.sync;
 
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
+import org.mockito.internal.matchers.Any;
 import seedu.agendum.model.task.Task;
 
 import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
 import java.time.LocalDateTime;
 import java.util.Optional;
 
-import static org.mockito.Mockito.mock;
-import static org.mockito.Mockito.when;
+import static org.mockito.Mockito.*;
 import static seedu.agendum.commons.core.Config.DEFAULT_DATA_DIR;
 
 public class SyncProviderGoogleTests {
-    private SyncProviderGoogle syncProviderGoogle;
     private static final File DATA_STORE_CREDENTIAL = new File(DEFAULT_DATA_DIR + "StoredCredential");
+    private static final File DATA_STORE_CREDENTIAL_TEST = new File("StoredCredentialForTesting");
+
+    private SyncProviderGoogle syncProviderGoogle;
+    private SyncManager mockSyncManager;
 
     @Before
     public void setUp() {
-        syncProviderGoogle = new SyncProviderGoogle();
+        try {
+            Files.copy(DATA_STORE_CREDENTIAL_TEST.toPath(), DATA_STORE_CREDENTIAL.toPath());
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+
+        mockSyncManager = mock(SyncManager.class);
+        syncProviderGoogle = spy(new SyncProviderGoogle());
+        syncProviderGoogle.setManager(mockSyncManager);
+    }
+
+    @After
+    public void tearDown() {
+        syncProviderGoogle.stop();
+    }
+
+    @Test
+    public void syncProviderGoogle_start_calendarAlreadyExists() {
+        syncProviderGoogle.deleteAgendumCalendar();
+        syncProviderGoogle.start();
+
+        verify(mockSyncManager).setSyncStatus(Sync.SyncStatus.RUNNING);
+    }
+
+    @Test
+    public void syncProviderGoogle_start_createCalendar() {
+        syncProviderGoogle.start();
+
+        verify(mockSyncManager).setSyncStatus(Sync.SyncStatus.RUNNING);
+    }
+
+    @Test
+    public void syncProviderGoogle_startIfNeeded_credentialsFound() {
+        syncProviderGoogle.startIfNeeded();
+        verify(syncProviderGoogle).start();
     }
 
     @Test
-    public void addevent() {
+    public void syncProviderGoogle_startIfNeeded_credentialsNotFound() {
+        DATA_STORE_CREDENTIAL.delete();
+        syncProviderGoogle.startIfNeeded();
+        verify(syncProviderGoogle, never()).start();
+    }
+
+    @Test
+    public void syncProviderGoogle_addEvent_successful() {
+        syncProviderGoogle.start();
+
         Task mockTask = mock(Task.class);
         Optional<LocalDateTime> fakeTime = Optional.of(LocalDateTime.now());
 
@@ -33,7 +82,9 @@ public void addevent() {
     }
 
     @Test
-    public void deleteEvent() {
+    public void syncProviderGoogle_deleteEvent_successful() {
+        syncProviderGoogle.start();
+
         Task mockTask = mock(Task.class);
         Optional<LocalDateTime> fakeTime = Optional.of(LocalDateTime.now());