mocking issue

Author: annzimmer

firebase-ml-modeldownloader/src/test/java/com/google/firebase/ml/modeldownloader/FirebaseModelDownloaderTest.java

@@ -739,7 +739,7 @@ public void listDownloadedModels_returnsModelList() throws Exception {
   @Test
   public void deleteDownloadedModel() throws Exception {
     doNothing().when(mockPrefs).clearModelDetails(eq(MODEL_NAME));
-    doNothing().when(mockFileManager).deleteAllModels(eq(MODEL_NAME));
+    when(mockFileManager.deleteAllModels(eq(MODEL_NAME))).thenReturn(true);
 
     TestOnCompleteListener<Void> onCompleteListener = new TestOnCompleteListener<>();
     Task<Void> task = firebaseModelDownloader.deleteDownloadedModel(MODEL_NAME);