Add simple test that verifies relations between field type classes

Author: przemekwitek

x-pack/plugin/core/src/test/java/org/elasticsearch/xpack/core/ml/dataframe/analyses/TypesTests.java

@@ -0,0 +1,21 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+package org.elasticsearch.xpack.core.ml.dataframe.analyses;
+
+import org.elasticsearch.common.util.set.Sets;
+import org.elasticsearch.test.ESTestCase;
+
+import static org.hamcrest.Matchers.empty;
+
+public class TypesTests extends ESTestCase {
+
+    public void testTypes() {
+        assertThat(Sets.intersection(Types.bool(), Types.categorical()), empty());
+        assertThat(Sets.intersection(Types.categorical(), Types.numerical()), empty());
+        assertThat(Sets.intersection(Types.numerical(), Types.bool()), empty());
+        assertThat(Sets.difference(Types.discreteNumerical(), Types.numerical()), empty());
+    }
+}