helix-core/src/test/java/org/apache/helix/controller/dataproviders/TestResourceControllerDataProvider.java

package org.apache.helix.controller.dataproviders;

/*
 * 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
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import java.util.ArrayList;
import java.util.HashMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import com.google.common.collect.ImmutableSet;
import org.apache.helix.model.IdealState;
import org.testng.Assert;
import org.testng.annotations.Test;

import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

public class TestResourceControllerDataProvider {
  @Test
  public void testStablePartitionListCache() {
    String resourceName = "TestResource";
    Set<String> partitionSetA = ImmutableSet.of("Partiton1", "Partiton2", "Partiton3");
    Set<String> partitionSetB = ImmutableSet.of("Partiton1", "Partiton2", "Partiton4");
    Map<String, IdealState> idealStateMap = new HashMap<>();
    IdealState is = mock(IdealState.class);
    when(is.getPartitionSet()).thenReturn(partitionSetA);
    when(is.getResourceName()).thenReturn(resourceName);
    idealStateMap.put(resourceName, is);

    ResourceControllerDataProvider dataProvider = new ResourceControllerDataProvider();

    List<String> cachedPartitionList =
        dataProvider.getStablePartitionList(resourceName);
    Assert.assertTrue(cachedPartitionList == null);

    // 1. Test refresh and get stable list
    dataProvider.refreshStablePartitionList(idealStateMap);
    List<String> cachedPartitionListA =
        dataProvider.getStablePartitionList(resourceName);
    Assert.assertTrue(cachedPartitionListA.size() == partitionSetA.size() && cachedPartitionListA
        .containsAll(partitionSetA));

    Set<String> partitionSetAWithDifferentOrder = new LinkedHashSet<>();
    partitionSetAWithDifferentOrder.add("Partiton3");
    partitionSetAWithDifferentOrder.add("Partiton2");
    partitionSetAWithDifferentOrder.add("Partiton1");
    // Verify that iterating this list will generate a different result
    List<String> tmpPartitionList = new ArrayList<>(partitionSetAWithDifferentOrder);
    Assert.assertFalse(cachedPartitionListA.equals(tmpPartitionList));
    // Verify that the cached stable partition list still return a list with the same order even
    // after refresh call.
    when(is.getPartitionSet()).thenReturn(partitionSetAWithDifferentOrder);
    dataProvider.refreshStablePartitionList(idealStateMap);
    Assert
        .assertTrue(dataProvider.getStablePartitionList(resourceName).equals(cachedPartitionListA));

    // 2. Test update the cache if items in the list have been changed.
    when(is.getPartitionSet()).thenReturn(partitionSetB);
    dataProvider.refreshStablePartitionList(idealStateMap);
    List<String> cachedPartitionListB =
        dataProvider.getStablePartitionList(resourceName);
    Assert.assertTrue(cachedPartitionListB.size() == partitionSetB.size() && cachedPartitionListB
        .containsAll(partitionSetB));

    // 3. Test removing item from the cache once the IdealState has been removed
    idealStateMap.clear();
    dataProvider.refreshStablePartitionList(idealStateMap);
    // Now, since the cache has been cleaned, the get will return different order.
    Assert.assertTrue(
        dataProvider.getStablePartitionList(resourceName) == null);
  }
}