@Test
public void testSyncError() {

  RuntimeException fakeError = new RuntimeException("fake error");
  // Reset the irrelevant expectations from setup. (only needed to silence the warnings).
  @SuppressWarnings("unchecked")
  UnaryCallable<String, String>[] innerCallableWrapper = new UnaryCallable[] {innerCallable};
  reset(innerCallableWrapper);
  when(innerCallable.futureCall(eq("failing test"), any(ApiCallContext.class)))
      .thenThrow(fakeError);
  try {
    tracedBatchingCallable.futureCall("failing test", callContext);
  } catch (RuntimeException e) {
    // ignored
  }
  verify(tracer, times(1)).operationFailed(fakeError);
}