/*
 * Copyright 2010-2015 Amazon.com, Inc. or its affiliates. All Rights Reserved.
 *
 * Licensed 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://aws.amazon.com/apache2.0
 *
 * This file 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 com.amazonaws.util;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;

import com.amazonaws.AmazonWebServiceRequest;
import com.amazonaws.ResponseMetadata;

import org.junit.Test;

import java.util.HashMap;
import java.util.Random;

/** Tests for the response metadata cache class. */
public class ResponseMetadataCacheTest {

    /** Tests that the cache correctly evicts the oldest entries. */
    @Test
    public void testEviction() {
        ResponseMetadataCache cache = new ResponseMetadataCache(3);

        AmazonWebServiceRequest key1 = new TestRequest();
        AmazonWebServiceRequest key2 = new TestRequest();
        AmazonWebServiceRequest key3 = new TestRequest();
        AmazonWebServiceRequest key4 = new TestRequest();
        ResponseMetadata metadata1 = newResponseMetadata();
        ResponseMetadata metadata2 = newResponseMetadata();
        ResponseMetadata metadata3 = newResponseMetadata();
        ResponseMetadata metadata4 = newResponseMetadata();

        // Fill the cache
        cache.add(key1, metadata1);
        cache.add(key2, metadata2);
        cache.add(key3, metadata3);

        // Verify all entries are still there
        assertEquals(metadata1, cache.get(key1));
        assertEquals(metadata2, cache.get(key2));
        assertEquals(metadata3, cache.get(key3));

        // Add another and make sure the oldest is evicted
        cache.add(key4, metadata4);
        assertNull(cache.get(key1));
        assertEquals(metadata2, cache.get(key2));
        assertEquals(metadata3, cache.get(key3));
        assertEquals(metadata4, cache.get(key4));
    }

    private class TestRequest extends AmazonWebServiceRequest {
    }

    private ResponseMetadata newResponseMetadata() {
        HashMap<String, String> metadata = new HashMap<String, String>();
        metadata.put("foo", "bar-" + new Random().nextLong());
        return new ResponseMetadata(metadata);
    }
}