/*
 * Copyright (C) 2009 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;

import com.google.common.collect.testing.features.CollectionFeature;
import com.google.common.collect.testing.features.CollectionSize;
import com.google.common.collect.testing.features.SetFeature;

import junit.framework.Test;
import junit.framework.TestSuite;

import java.lang.reflect.Method;
import java.util.AbstractSet;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.EnumSet;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashSet;
import java.util.Set;
import java.util.SortedSet;
import java.util.TreeSet;
import java.util.concurrent.CopyOnWriteArraySet;

/**
 * Generates a test suite covering the {@link Set} implementations in the
 * {@link java.util} package. Can be subclassed to specify tests that should
 * be suppressed.
 *
 * @author Kevin Bourrillion
 */
public class TestsForSetsInJavaUtil {
  public static Test suite() {
    return new TestsForSetsInJavaUtil().allTests();
  }

  public Test allTests() {
    TestSuite suite = new TestSuite("java.util Sets");
    suite.addTest(testsForEmptySet());
    suite.addTest(testsForSingletonSet());
    suite.addTest(testsForHashSet());
    suite.addTest(testsForLinkedHashSet());
    suite.addTest(testsForEnumSet());
    suite.addTest(testsForTreeSetNatural());
    suite.addTest(testsForTreeSetWithComparator());
    suite.addTest(testsForCopyOnWriteArraySet());
    suite.addTest(testsForUnmodifiableSet());
    suite.addTest(testsForCheckedSet());
    suite.addTest(testsForAbstractSet());
    suite.addTest(testsForBadlyCollidingHashSet());

    return suite;
  }

  protected Collection<Method> suppressForEmptySet() {
    return Collections.emptySet();
  }
  protected Collection<Method> suppressForSingletonSet() {
    return Collections.emptySet();
  }
  protected Collection<Method> suppressForHashSet() {
    return Collections.emptySet();
  }
  protected Collection<Method> suppressForLinkedHashSet() {
    return Collections.emptySet();
  }
  protected Collection<Method> suppressForEnumSet() {
    return Collections.emptySet();
  }
  protected Collection<Method> suppressForTreeSetNatural() {
    return Collections.emptySet();
  }
  protected Collection<Method> suppressForTreeSetWithComparator() {
    return Collections.emptySet();
  }
  protected Collection<Method> suppressForCopyOnWriteArraySet() {
    return Collections.emptySet();
  }
  protected Collection<Method> suppressForUnmodifiableSet() {
    return Collections.emptySet();
  }
  protected Collection<Method> suppressForCheckedSet() {
    return Collections.emptySet();
  }
  protected Collection<Method> suppressForAbstractSet() {
    return Collections.emptySet();
  }

  public Test testsForEmptySet() {
    return SetTestSuiteBuilder
        .using(new TestStringSetGenerator() {
            @Override public Set<String> create(String[] elements) {
              return Collections.emptySet();
            }
          })
        .named("emptySet")
        .withFeatures(
            CollectionFeature.NONE,
            CollectionSize.ZERO)
        .suppressing(suppressForEmptySet())
        .createTestSuite();
  }

  public Test testsForSingletonSet() {
    return SetTestSuiteBuilder
        .using(new TestStringSetGenerator() {
            @Override public Set<String> create(String[] elements) {
              return Collections.singleton(elements[0]);
            }
          })
        .named("singleton")
        .withFeatures(
            CollectionFeature.NONE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionSize.ONE)
        .suppressing(suppressForSingletonSet())
        .createTestSuite();
  }

  public Test testsForHashSet() {
    return SetTestSuiteBuilder
        .using(new TestStringSetGenerator() {
            @Override public Set<String> create(String[] elements) {
              return new HashSet<String>(MinimalCollection.of(elements));
            }
          })
        .named("HashSet")
        .withFeatures(
            SetFeature.GENERAL_PURPOSE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionSize.ANY)
        .suppressing(suppressForHashSet())
        .createTestSuite();
  }

  public Test testsForLinkedHashSet() {
    return SetTestSuiteBuilder
        .using(new TestStringSetGenerator() {
            @Override public Set<String> create(String[] elements) {
              return new LinkedHashSet<String>(MinimalCollection.of(elements));
            }
          })
        .named("LinkedHashSet")
        .withFeatures(
            SetFeature.GENERAL_PURPOSE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionFeature.KNOWN_ORDER,
            CollectionSize.ANY)
        .suppressing(suppressForLinkedHashSet())
        .createTestSuite();
  }

  public Test testsForEnumSet() {
    return SetTestSuiteBuilder
        .using(new TestEnumSetGenerator() {
            @Override public Set<AnEnum> create(AnEnum[] elements) {
              return (elements.length == 0)
                  ? EnumSet.noneOf(AnEnum.class)
                  : EnumSet.copyOf(MinimalCollection.of(elements));
            }
          })
        .named("EnumSet")
        .withFeatures(
            SetFeature.GENERAL_PURPOSE,
            CollectionFeature.KNOWN_ORDER,
            CollectionFeature.RESTRICTS_ELEMENTS,
            CollectionSize.ANY)
        .suppressing(suppressForEnumSet())
        .createTestSuite();
  }

  public Test testsForTreeSetNatural() {
    return SetTestSuiteBuilder
        .using(new TestStringSortedSetGenerator() {
            @Override public SortedSet<String> create(String[] elements) {
              return new TreeSet<String>(MinimalCollection.of(elements));
            }
          })
        .named("TreeSet, natural")
        .withFeatures(
            SetFeature.GENERAL_PURPOSE,
            CollectionFeature.KNOWN_ORDER,
            CollectionSize.ANY)
        .suppressing(suppressForTreeSetNatural())
        .createTestSuite();
  }

  public Test testsForTreeSetWithComparator() {
    return SetTestSuiteBuilder
        .using(new TestStringSortedSetGenerator() {
            @Override public SortedSet<String> create(String[] elements) {
              SortedSet<String> set
                  = new TreeSet<String>(arbitraryNullFriendlyComparator());
              Collections.addAll(set, elements);
              return set;
            }
          })
        .named("TreeSet, with comparator")
        .withFeatures(
            SetFeature.GENERAL_PURPOSE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionFeature.KNOWN_ORDER,
            CollectionSize.ANY)
        .suppressing(suppressForTreeSetWithComparator())
        .createTestSuite();
  }

  public Test testsForCopyOnWriteArraySet() {
    return SetTestSuiteBuilder
        .using(new TestStringSetGenerator() {
            @Override public Set<String> create(String[] elements) {
              return new CopyOnWriteArraySet<String>(
                  MinimalCollection.of(elements));
            }
          })
        .named("CopyOnWriteArraySet")
        .withFeatures(
            SetFeature.GENERAL_PURPOSE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionFeature.KNOWN_ORDER,
            CollectionSize.ANY)
        .suppressing(suppressForCopyOnWriteArraySet())
        .createTestSuite();
  }

  public Test testsForUnmodifiableSet() {
    return SetTestSuiteBuilder
        .using(new TestStringSetGenerator() {
            @Override public Set<String> create(String[] elements) {
              Set<String> innerSet = new HashSet<String>();
              Collections.addAll(innerSet, elements);
              return Collections.unmodifiableSet(innerSet);
            }
          })
        .named("unmodifiableSet/HashSet")
        .withFeatures(
            CollectionFeature.NONE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionSize.ANY)
        .suppressing(suppressForUnmodifiableSet())
        .createTestSuite();
  }

  public Test testsForCheckedSet() {
    return SetTestSuiteBuilder
        .using(new TestStringSetGenerator() {
            @Override public Set<String> create(String[] elements) {
              Set<String> innerSet = new HashSet<String>();
              Collections.addAll(innerSet, elements);
              return Collections.checkedSet(innerSet, String.class);
            }
          })
        .named("checkedSet/HashSet")
        .withFeatures(
            SetFeature.GENERAL_PURPOSE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionFeature.RESTRICTS_ELEMENTS,
            CollectionSize.ANY)
        .suppressing(suppressForCheckedSet())
        .createTestSuite();
  }

  public Test testsForAbstractSet() {
    return SetTestSuiteBuilder
        .using(new TestStringSetGenerator () {
            @Override protected Set<String> create(String[] elements) {
              final String[] deduped = dedupe(elements);
              return new AbstractSet<String>() {
                @Override public int size() {
                  return deduped.length;
                }
                @Override public Iterator<String> iterator() {
                  return MinimalCollection.of(deduped).iterator();
                }
              };
            }
          })
        .named("AbstractSet")
        .withFeatures(
            CollectionFeature.NONE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionFeature.KNOWN_ORDER, // in this case, anyway
            CollectionSize.ANY)
        .suppressing(suppressForAbstractSet())
        .createTestSuite();
  }

  public Test testsForBadlyCollidingHashSet() {
    return SetTestSuiteBuilder
        .using(new TestCollidingSetGenerator() {
            @Override
            public Set<Object> create(Object... elements) {
              return new HashSet<Object>(MinimalCollection.of(elements));
            }
          })
        .named("badly colliding HashSet")
        .withFeatures(
            SetFeature.GENERAL_PURPOSE,
            CollectionFeature.ALLOWS_NULL_VALUES,
            CollectionSize.SEVERAL)
        .suppressing(suppressForHashSet())
        .createTestSuite();
  }

  private static String[] dedupe(String[] elements) {
    Set<String> tmp = new LinkedHashSet<String>();
    Collections.addAll(tmp, elements);
    return tmp.toArray(new String[0]);
  }

  static <T> Comparator<T> arbitraryNullFriendlyComparator() {
    return new Comparator<T>() {
      @Override
      public int compare(T left, T right) {
        return String.valueOf(left).compareTo(String.valueOf(right));
      }
    };
  }
}
