mock an executor service with power mock

Question

I have made my function async with executor service but while executing test cases are not executing the executor service method.

The update code similar to:

void method1(Status status) {

    executorService.submit(() -> {
        try () {
            method2();
        } catch (Exception exception) {

            throw new CustomException(exception.getMessage(), exception);
        }
    });

}

while debuging the exixting testcase i found that the executorService.submit was skipped. I tried to mock the submit method but not working.

@Test(expected = CustomException.class)
public void testSatuse() throws Exception {
    Status mocktatus = getStatusMock("XXX", "XXXX");
    PowerMockito.doNothing().when(httpResponse).close();
    CustomException exception = PowerMockito.mock(CustomException.class);
    PowerMockito.when(httpClient.execute(Mockito.any())).thenReturn(httpResponse);
    Future<String> futureMock = Mockito.mock(Future.class);
    PowerMockito.when(executorServiceMock.submit(Mockito.any(Runnable.class)))
            .thenAnswer(invocation -> {
                Callable<String> task = invocation.getArgument(0);
                return futureMock;
            });
    PowerMockito.when(httpResponse.getStatusLine()).thenThrow(exception);
    myClassName.method1(mockStatus);
 }

If i change the @Test(expected = CustomException.class) to @Test(expected = Exception.class) it will work but I can not do that. What should be the best practice to solve this so that the method2() is invoked.