public TopicName createTopic(String topicName) {
    checkArgument(!topicName.isEmpty(), "topicName can not be empty");
    checkIsUsable();

    TopicName name = getTopicName(topicName);
    return createTopicInternal(name);
  }
@Test
  public void testCreateTopicShouldCreate() {
    when(topicAdminClient.createTopic(any(TopicName.class))).thenReturn(topic);

    TopicName createTopic = testManager.createTopic("topic-name");

    assertThat(createTopic).isNotNull();
    verify(topicAdminClient).createTopic(topicNameCaptor.capture());
    TopicName actualTopicName = topicNameCaptor.getValue();
    assertThat(actualTopicName.getProject()).isEqualTo(PROJECT_ID);
    assertThat(actualTopicName.getTopic()).matches(TEST_ID + "-\\d{17}-topic-name");
  }