/*
    * Copyright (C) 2008 The Guava Authors
    *
    * 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://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 com.google.common.collect.testing.testers;
  
  import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_QUERIES;
  import static com.google.common.collect.testing.features.CollectionFeature.ALLOWS_NULL_VALUES;
  import static com.google.common.collect.testing.features.CollectionFeature.FAILS_FAST_ON_CONCURRENT_MODIFICATION;
  import static com.google.common.collect.testing.features.CollectionFeature.SUPPORTS_REMOVE;
  import static com.google.common.collect.testing.features.CollectionSize.SEVERAL;
  import static com.google.common.collect.testing.features.CollectionSize.ZERO;
  
  import com.google.common.annotations.GwtCompatible;
  import com.google.common.collect.testing.AbstractCollectionTester;
  import com.google.common.collect.testing.WrongType;
  import com.google.common.collect.testing.features.CollectionFeature;
  import com.google.common.collect.testing.features.CollectionSize;
  
  import java.util.ConcurrentModificationException;
  import java.util.Iterator;
  
  /**
   * A generic JUnit test which tests {@code remove} operations on a collection.
   * Can't be invoked directly; please see
   * {@link com.google.common.collect.testing.CollectionTestSuiteBuilder}.
   *
   * @author George van den Driessche
   */
  @SuppressWarnings("unchecked") // too many "unchecked generic array creations"
  @GwtCompatible
  public class CollectionRemoveTester<E> extends AbstractCollectionTester<E> {
    @CollectionFeature.Require(SUPPORTS_REMOVE)
    @CollectionSize.Require(absent = ZERO)
    public void testRemove_present() {
      int initialSize = collection.size();
      assertTrue("remove(present) should return true",
          collection.remove(samples.e0));
      assertEquals("remove(present) should decrease a collection's size by one.",
          initialSize - 1, collection.size());
      expectMissing(samples.e0);
    }
  
    @CollectionFeature.Require({SUPPORTS_REMOVE,
        FAILS_FAST_ON_CONCURRENT_MODIFICATION})
    @CollectionSize.Require(SEVERAL)
    public void testRemovePresentConcurrentWithIteration() {
      try {
        Iterator<E> iterator = collection.iterator();
        assertTrue(collection.remove(samples.e0));
        iterator.next();
        fail("Expected ConcurrentModificationException");
      } catch (ConcurrentModificationException expected) {
        // success
      }
    }
  
    @CollectionFeature.Require(SUPPORTS_REMOVE)
    public void testRemove_notPresent() {
      assertFalse("remove(notPresent) should return false",
          collection.remove(samples.e3));
      expectUnchanged();
    }
  
    @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_VALUES})
    @CollectionSize.Require(absent = ZERO)
    public void testRemove_nullPresent() {
      collection = getSubjectGenerator().create(createArrayWithNullElement());
  
      int initialSize = collection.size();
      assertTrue("remove(null) should return true", collection.remove(null));
      assertEquals("remove(present) should decrease a collection's size by one.",
          initialSize - 1, collection.size());
      expectMissing((E) null);
    }
  
    @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
    @CollectionSize.Require(absent = ZERO)
    public void testRemove_unsupported() {
      try {
        collection.remove(samples.e0);
        fail("remove(present) should throw UnsupportedOperationException");
      } catch (UnsupportedOperationException expected) {
      }
      expectUnchanged();
      assertTrue("remove(present) should not remove the element",
          collection.contains(samples.e0));
   }
 
   @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
   public void testRemove_unsupportedNotPresent() {
     try {
       assertFalse("remove(notPresent) should return false or throw "
           + "UnsupportedOperationException",
           collection.remove(samples.e3));
     } catch (UnsupportedOperationException tolerated) {
     }
     expectUnchanged();
     expectMissing(samples.e3);
   }
 
   @CollectionFeature.Require(
       value = SUPPORTS_REMOVE,
       absent = ALLOWS_NULL_QUERIES)
   public void testRemove_nullNotSupported() {
     try {
       assertFalse("remove(null) should return false or throw "
           + "NullPointerException",
           collection.remove(null));
     } catch (NullPointerException tolerated) {
     }
     expectUnchanged();
   }
 
   @CollectionFeature.Require({SUPPORTS_REMOVE, ALLOWS_NULL_QUERIES})
   public void testRemove_nullAllowed() {
     assertFalse("remove(null) should return false", collection.remove(null));
     expectUnchanged();
   }
 
   @CollectionFeature.Require(absent = SUPPORTS_REMOVE)
   @CollectionSize.Require(absent = ZERO)
   public void testIteratorRemove_unsupported() {
     Iterator<E> iterator = collection.iterator();
     iterator.next();
     try {
       iterator.remove();
       fail("iterator.remove() should throw UnsupportedOperationException");
     } catch (UnsupportedOperationException expected) {
     }
     expectUnchanged();
     assertTrue(collection.contains(samples.e0));
   }
 
   @CollectionFeature.Require(SUPPORTS_REMOVE)
   public void testRemove_wrongType() {
     try {
       assertFalse(collection.remove(WrongType.VALUE));
     } catch (ClassCastException tolerated) {
     }
     expectUnchanged();
   }
 }