/*
 * 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.
 */

package org.apache.flink.core.memory;

import org.junit.Test;

import java.lang.reflect.Field;

import static org.junit.Assert.*;

public class MemorySegmentFactoryTest {

	@Test
	public void testInitializationToHeapSegments() throws Exception {
		clearSegmentFactory();

		assertFalse(MemorySegmentFactory.isInitialized());
		assertTrue(MemorySegmentFactory.initializeIfNotInitialized(HeapMemorySegment.FACTORY));
		assertTrue(MemorySegmentFactory.isInitialized());

		assertTrue(MemorySegmentFactory.initializeIfNotInitialized(HeapMemorySegment.FACTORY));
		assertFalse(MemorySegmentFactory.initializeIfNotInitialized(HybridMemorySegment.FACTORY));

		assertEquals(HeapMemorySegment.FACTORY, MemorySegmentFactory.getFactory());
	}

	@Test
	public void testInitializationToOffHeapSegments() throws Exception {
		clearSegmentFactory();

		assertFalse(MemorySegmentFactory.isInitialized());
		assertTrue(MemorySegmentFactory.initializeIfNotInitialized(HybridMemorySegment.FACTORY));
		assertTrue(MemorySegmentFactory.isInitialized());

		assertTrue(MemorySegmentFactory.initializeIfNotInitialized(HybridMemorySegment.FACTORY));
		assertFalse(MemorySegmentFactory.initializeIfNotInitialized(HeapMemorySegment.FACTORY));

		assertEquals(HybridMemorySegment.FACTORY, MemorySegmentFactory.getFactory());
	}

	private static void clearSegmentFactory() throws Exception {
		Field factoryField = MemorySegmentFactory.class.getDeclaredField("factory");
		factoryField.setAccessible(true);
		factoryField.set(null, null);
	}
}