* **`ESTestCase`**: The base class of all tests. It is typically extended
  directly by unit tests.
* **`ESSingleNodeTestCase`**: This test case sets up a cluster that has a
  single node.
* **`ESIntegTestCase`**: An integration test case that creates a cluster that
  might have multiple nodes.
* **`ESRestTestCase`**: An integration tests that interacts with an external

            testsRule.baseClass("org.apache.lucene.util.LuceneTestCase");
            TestingConventionRule itRule = t.getNaming().maybeCreate("IT");
            itRule.baseClass("org.elasticsearch.test.ESIntegTestCase");
            itRule.baseClass("org.elasticsearch.test.rest.ESRestTestCase");
        });
        return testingConventions;
    }

            t.getNaming().create("IT", testingConventionRule -> {
                testingConventionRule.baseClass("org.elasticsearch.test.ESIntegTestCase");
                testingConventionRule.baseClass("org.elasticsearch.test.rest.ESRestTestCase");
                testingConventionRule.baseClass("org.elasticsearch.test.ESSingleNodeTestCase");
            });
        });