--- /dev/null
+package org.apache.lucene.index;
+
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Method;
+import java.lang.reflect.Modifier;
+import java.util.Arrays;
+
+import org.apache.lucene.util.LuceneTestCase;
+import org.junit.Test;
+
+public class TestNoMergeScheduler extends LuceneTestCase {
+
+ @Test
+ public void testNoMergeScheduler() throws Exception {
+ MergeScheduler ms = NoMergeScheduler.INSTANCE;
+ ms.close();
+ ms.merge(null);
+ }
+
+ @Test
+ public void testFinalSingleton() throws Exception {
+ assertTrue(Modifier.isFinal(NoMergeScheduler.class.getModifiers()));
+ Constructor<?>[] ctors = NoMergeScheduler.class.getDeclaredConstructors();
+ assertEquals("expected 1 private ctor only: " + Arrays.toString(ctors), 1, ctors.length);
+ assertTrue("that 1 should be private: " + ctors[0], Modifier.isPrivate(ctors[0].getModifiers()));
+ }
+
+ @Test
+ public void testMethodsOverridden() throws Exception {
+ // Ensures that all methods of MergeScheduler are overridden. That's
+ // important to ensure that NoMergeScheduler overrides everything, so that
+ // no unexpected behavior/error occurs
+ for (Method m : NoMergeScheduler.class.getMethods()) {
+ // getDeclaredMethods() returns just those methods that are declared on
+ // NoMergeScheduler. getMethods() returns those that are visible in that
+ // context, including ones from Object. So just filter out Object. If in
+ // the future MergeScheduler will extend a different class than Object,
+ // this will need to change.
+ if (m.getDeclaringClass() != Object.class) {
+ assertTrue(m + " is not overridden !", m.getDeclaringClass() == NoMergeScheduler.class);
+ }
+ }
+ }
+
+}