@Test
  public void createExistingDatabase() {
    Throwable exception = Assertions.assertThrows(AlreadyExistsException.class,
        () -> client.createDatabase(TEST_DATABASE));
  }
Verify that an attempt to create an existing database throws AlreadyExistsException.
standalone-metastore/metastore-tools/tools-common/src/test/java/org/apache/hadoop/hive/metastore/tools/HMSClientTest.java