### Question:
ConfigStorageClient { public synchronized Void clear() { context.deleteFile(fileName); return null; } private  ConfigStorageClient(Context context, String fileName); synchronized Void write(ConfigContainer container); @Nullable synchronized ConfigContainer read(); synchronized Void clear(); static synchronized ConfigStorageClient getInstance(Context context, String fileName); @VisibleForTesting static synchronized void clearInstancesForTest();  }### Answer:
@Test public void clear_emptyFile_doesNothing() throws Exception { storageClient.clear(); assertThat(getFileAsString()).isEmpty(); }