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Java example source code file (FluentIterableTest.java)

This example Java source code file (FluentIterableTest.java) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

annotation, collection, fluentiterable, function, illegalargumentexception, integer, iterable, iterator, list, nullpointerexception, object, override, string, threading, threads, typea, util

The FluentIterableTest.java Java example source code

/*
 * 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;

import static com.google.common.collect.Lists.newArrayList;
import static com.google.common.truth.Truth.assertThat;
import static java.util.Arrays.asList;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.GwtIncompatible;
import com.google.common.base.Function;
import com.google.common.base.Functions;
import com.google.common.base.Joiner;
import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.testing.IteratorFeature;
import com.google.common.collect.testing.IteratorTester;
import com.google.common.testing.NullPointerTester;

import junit.framework.AssertionFailedError;
import junit.framework.TestCase;

import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.SortedSet;
import java.util.concurrent.TimeUnit;

import javax.annotation.Nullable;

/**
 * Unit test for {@link FluentIterable}.
 *
 * @author Marcin Mikosik
 */
@GwtCompatible(emulated = true)
public class FluentIterableTest extends TestCase {

  @GwtIncompatible // NullPointerTester
  public void testNullPointerExceptions() {
    NullPointerTester tester = new NullPointerTester();
    tester.testAllPublicStaticMethods(FluentIterable.class);
  }

  public void testFromArrayAndAppend() {
    FluentIterable<TimeUnit> units =
        FluentIterable.from(TimeUnit.values()).append(TimeUnit.SECONDS);
  }

  public void testFromArrayAndIteratorRemove() {
    FluentIterable<TimeUnit> units = FluentIterable.from(TimeUnit.values());
    try {
      Iterables.removeIf(units, Predicates.equalTo(TimeUnit.SECONDS));
      fail("Expected an UnsupportedOperationException to be thrown but it wasn't.");
    } catch (UnsupportedOperationException expected) {
    }
  }

  public void testOfArrayAndIteratorRemove() {
    FluentIterable<TimeUnit> units = FluentIterable.of(TimeUnit.values());
    assertTrue(Iterables.removeIf(units, Predicates.equalTo(TimeUnit.SECONDS)));
  }

  public void testFrom() {
    assertEquals(ImmutableList.of(1, 2, 3, 4),
        Lists.newArrayList(FluentIterable.from(ImmutableList.of(1, 2, 3, 4))));
  }

  @SuppressWarnings("deprecation") // test of deprecated method
  public void testFrom_alreadyFluentIterable() {
    FluentIterable<Integer> iterable = FluentIterable.from(asList(1));
    assertSame(iterable, FluentIterable.from(iterable));
  }

  public void testOf() {
    assertEquals(ImmutableList.of(1, 2, 3, 4),
        Lists.newArrayList(FluentIterable.of(1, 2, 3, 4)));
  }

  public void testOfArray() {
    assertEquals(ImmutableList.of("1", "2", "3", "4"),
        Lists.newArrayList(FluentIterable.of(new Object[] {"1", "2", "3", "4"})));
  }

  public void testFromArray() {
    assertEquals(ImmutableList.of("1", "2", "3", "4"),
        Lists.newArrayList(FluentIterable.from(new Object[] {"1", "2", "3", "4"})));
  }

  public void testOf_empty() {
    assertEquals(ImmutableList.of(), Lists.newArrayList(FluentIterable.of()));
  }

  // Exhaustive tests are in IteratorsTest. These are copied from IterablesTest.
  public void testConcatIterable() {
    List<Integer> list1 = newArrayList(1);
    List<Integer> list2 = newArrayList(4);

    @SuppressWarnings("unchecked")
    List<List input = newArrayList(list1, list2);

    FluentIterable<Integer> result = FluentIterable.concat(input);
    assertEquals(asList(1, 4), newArrayList(result));

    // Now change the inputs and see result dynamically change as well

    list1.add(2);
    List<Integer> list3 = newArrayList(3);
    input.add(1, list3);

    assertEquals(asList(1, 2, 3, 4), newArrayList(result));
    assertEquals("[1, 2, 3, 4]", result.toString());
  }

  public void testConcatVarargs() {
    List<Integer> list1 = newArrayList(1);
    List<Integer> list2 = newArrayList(4);
    List<Integer> list3 = newArrayList(7, 8);
    List<Integer> list4 = newArrayList(9);
    List<Integer> list5 = newArrayList(10);
    @SuppressWarnings("unchecked")
    FluentIterable<Integer> result = FluentIterable.concat(list1, list2, list3, list4, list5);
    assertEquals(asList(1, 4, 7, 8, 9, 10), newArrayList(result));
    assertEquals("[1, 4, 7, 8, 9, 10]", result.toString());
  }

  public void testConcatNullPointerException() {
    List<Integer> list1 = newArrayList(1);
    List<Integer> list2 = newArrayList(4);

    try {
      FluentIterable.concat(list1, null, list2);
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testConcatPeformingFiniteCycle() {
    Iterable<Integer> iterable = asList(1, 2, 3);
    int n = 4;
    FluentIterable<Integer> repeated = FluentIterable.concat(Collections.nCopies(n, iterable));
    assertThat(repeated).containsExactly(1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3).inOrder();
  }

  interface X {}

  interface Y {}

  static class A implements X, Y {}

  static class B implements X, Y {}

  /**
   * This test passes if the {@code concat(…).filter(…).filter(…)} statement at the end compiles.
   * That statement compiles only if {@link FluentIterable#concat concat(aIterable, bIterable)}
   * returns a {@link FluentIterable} of elements of an anonymous type whose supertypes are the
   * <a href="https://docs.oracle.com/javase/specs/jls/se7/html/jls-4.html#jls-4.9">intersection
   * of the supertypes of {@code A} and the supertypes of {@code B}.
   */
  public void testConcatIntersectionType() {
    Iterable<A> aIterable = ImmutableList.of();
    Iterable<B> bIterable = ImmutableList.of();

    Predicate<X> xPredicate = Predicates.alwaysTrue();
    Predicate<Y> yPredicate = Predicates.alwaysTrue();

    FluentIterable<?> unused =
        FluentIterable.concat(aIterable, bIterable).filter(xPredicate).filter(yPredicate);

    /* The following fails to compile:
     *
     * The method append(Iterable<? extends FluentIterableTest.A>) in the type
     * FluentIterable<FluentIterableTest.A> is not applicable for the arguments
     * (Iterable<FluentIterableTest.B>)
     */
    // FluentIterable.from(aIterable).append(bIterable);

    /* The following fails to compile:
     *
     * The method filter(Predicate<? super Object>) in the type FluentIterable is not
     * applicable for the arguments (Predicate<FluentIterableTest.X>)
     */
    // FluentIterable.of().append(aIterable).append(bIterable).filter(xPredicate);
  }

  public void testSize0() {
    assertEquals(0, FluentIterable.<String>of().size());
  }

  public void testSize1Collection() {
    assertEquals(1, FluentIterable.from(asList("a")).size());
  }

  public void testSize2NonCollection() {
    Iterable<Integer> iterable = new Iterable() {
      @Override
      public Iterator<Integer> iterator() {
        return asList(0, 1).iterator();
      }
    };
    assertEquals(2, FluentIterable.from(iterable).size());
  }

  public void testSize_collectionDoesntIterate() {
    List<Integer> nums = asList(1, 2, 3, 4, 5);
    List<Integer> collection = new ArrayList(nums) {
      @Override public Iterator<Integer> iterator() {
        throw new AssertionFailedError("Don't iterate me!");
      }
    };
    assertEquals(5, FluentIterable.from(collection).size());
  }

  public void testContains_nullSetYes() {
    Iterable<String> set = Sets.newHashSet("a", null, "b");
    assertTrue(FluentIterable.from(set).contains(null));
  }

  public void testContains_nullSetNo() {
    Iterable<String> set = ImmutableSortedSet.of("a", "b");
    assertFalse(FluentIterable.from(set).contains(null));
  }

  public void testContains_nullIterableYes() {
    Iterable<String> iterable = iterable("a", null, "b");
    assertTrue(FluentIterable.from(iterable).contains(null));
  }

  public void testContains_nullIterableNo() {
    Iterable<String> iterable = iterable("a", "b");
    assertFalse(FluentIterable.from(iterable).contains(null));
  }

  public void testContains_nonNullSetYes() {
    Iterable<String> set = Sets.newHashSet("a", null, "b");
    assertTrue(FluentIterable.from(set).contains("b"));
  }

  public void testContains_nonNullSetNo() {
    Iterable<String> set = Sets.newHashSet("a", "b");
    assertFalse(FluentIterable.from(set).contains("c"));
  }

  public void testContains_nonNullIterableYes() {
    Iterable<String> set = iterable("a", null, "b");
    assertTrue(FluentIterable.from(set).contains("b"));
  }

  public void testContains_nonNullIterableNo() {
    Iterable<String> iterable = iterable("a", "b");
    assertFalse(FluentIterable.from(iterable).contains("c"));
  }

  public void testOfToString() {
    assertEquals("[yam, bam, jam, ham]",
        FluentIterable.of("yam", "bam", "jam", "ham").toString());
  }

  public void testToString() {
    assertEquals("[]", FluentIterable.from(Collections.emptyList()).toString());
    assertEquals("[]", FluentIterable.<String>of().toString());

    assertEquals("[yam, bam, jam, ham]",
        FluentIterable.from(asList("yam", "bam", "jam", "ham")).toString());
  }

  public void testCycle() {
    FluentIterable<String> cycle = FluentIterable.from(asList("a", "b")).cycle();

    int howManyChecked = 0;
    for (String string : cycle) {
      String expected = (howManyChecked % 2 == 0) ? "a" : "b";
      assertEquals(expected, string);
      if (howManyChecked++ == 5) {
        break;
      }
    }

    // We left the last iterator pointing to "b". But a new iterator should
    // always point to "a".
    assertEquals("a", cycle.iterator().next());
  }

  public void testCycle_emptyIterable() {
    FluentIterable<Integer> cycle = FluentIterable.of().cycle();
    assertFalse(cycle.iterator().hasNext());
  }

  public void testCycle_removingAllElementsStopsCycle() {
    FluentIterable<Integer> cycle = fluent(1, 2).cycle();
    Iterator<Integer> iterator = cycle.iterator();
    iterator.next();
    iterator.remove();
    iterator.next();
    iterator.remove();
    assertFalse(iterator.hasNext());
    assertFalse(cycle.iterator().hasNext());
  }

  public void testAppend() {
    FluentIterable<Integer> result =
        FluentIterable.<Integer>from(asList(1, 2, 3)).append(Lists.newArrayList(4, 5, 6));
    assertEquals(asList(1, 2, 3, 4, 5, 6), Lists.newArrayList(result));
    assertEquals("[1, 2, 3, 4, 5, 6]", result.toString());

    result = FluentIterable.<Integer>from(asList(1, 2, 3)).append(4, 5, 6);
    assertEquals(asList(1, 2, 3, 4, 5, 6), Lists.newArrayList(result));
    assertEquals("[1, 2, 3, 4, 5, 6]", result.toString());
  }

  public void testAppend_toEmpty() {
    FluentIterable<Integer> result =
        FluentIterable.<Integer>of().append(Lists.newArrayList(1, 2, 3));
    assertEquals(asList(1, 2, 3), Lists.newArrayList(result));
  }

  public void testAppend_emptyList() {
    FluentIterable<Integer> result =
        FluentIterable.<Integer>from(asList(1, 2, 3)).append(Lists.newArrayList());
    assertEquals(asList(1, 2, 3), Lists.newArrayList(result));
  }

  public void testAppend_nullPointerException() {
    try {
      FluentIterable<Integer> unused =
          FluentIterable.<Integer>from(asList(1, 2)).append((List) null);
      fail("Appending null iterable should throw NPE.");
    } catch (NullPointerException expected) {
    }
  }

  /*
   * Tests for partition(int size) method.
   */

  /*
   * Tests for partitionWithPadding(int size) method.
   */

  public void testFilter() {
    FluentIterable<String> filtered =
        FluentIterable.from(asList("foo", "bar")).filter(Predicates.equalTo("foo"));

    List<String> expected = Collections.singletonList("foo");
    List<String> actual = Lists.newArrayList(filtered);
    assertEquals(expected, actual);
    assertCanIterateAgain(filtered);
    assertEquals("[foo]", filtered.toString());
  }

  private static class TypeA {}
  private interface TypeB {}
  private static class HasBoth extends TypeA implements TypeB {}

  @GwtIncompatible // Iterables.filter(Iterable, Class)
  public void testFilterByType() throws Exception {
    HasBoth hasBoth = new HasBoth();
    FluentIterable<TypeA> alist =
        FluentIterable.from(asList(new TypeA(), new TypeA(), hasBoth, new TypeA()));
    Iterable<TypeB> blist = alist.filter(TypeB.class);
    assertThat(blist).containsExactly(hasBoth).inOrder();
  }

  public void testAnyMatch() {
    ArrayList<String> list = Lists.newArrayList();
    FluentIterable<String> iterable = FluentIterable.from(list);
    Predicate<String> predicate = Predicates.equalTo("pants");

    assertFalse(iterable.anyMatch(predicate));
    list.add("cool");
    assertFalse(iterable.anyMatch(predicate));
    list.add("pants");
    assertTrue(iterable.anyMatch(predicate));
  }

  public void testAllMatch() {
    List<String> list = Lists.newArrayList();
    FluentIterable<String> iterable = FluentIterable.from(list);
    Predicate<String> predicate = Predicates.equalTo("cool");

    assertTrue(iterable.allMatch(predicate));
    list.add("cool");
    assertTrue(iterable.allMatch(predicate));
    list.add("pants");
    assertFalse(iterable.allMatch(predicate));
  }

  public void testFirstMatch() {
    FluentIterable<String> iterable = FluentIterable.from(Lists.newArrayList("cool", "pants"));
    assertThat(iterable.firstMatch(Predicates.equalTo("cool"))).hasValue("cool");
    assertThat(iterable.firstMatch(Predicates.equalTo("pants"))).hasValue("pants");
    assertThat(iterable.firstMatch(Predicates.alwaysFalse())).isAbsent();
    assertThat(iterable.firstMatch(Predicates.alwaysTrue())).hasValue("cool");
  }

  private static final class IntegerValueOfFunction implements Function<String, Integer> {
    @Override
    public Integer apply(String from) {
      return Integer.valueOf(from);
    }
  }

  public void testTransformWith() {
    List<String> input = asList("1", "2", "3");
    Iterable<Integer> iterable =
        FluentIterable.from(input).transform(new IntegerValueOfFunction());

    assertEquals(asList(1, 2, 3), Lists.newArrayList(iterable));
    assertCanIterateAgain(iterable);
    assertEquals("[1, 2, 3]", iterable.toString());
  }

  public void testTransformWith_poorlyBehavedTransform() {
    List<String> input = asList("1", null, "3");
    Iterable<Integer> iterable =
        FluentIterable.from(input).transform(new IntegerValueOfFunction());

    Iterator<Integer> resultIterator = iterable.iterator();
    resultIterator.next();

    try {
      resultIterator.next();
      fail("Transforming null to int should throw NumberFormatException");
    } catch (NumberFormatException expected) {
    }
  }

  private static final class StringValueOfFunction implements Function<Integer, String> {
    @Override
    public String apply(Integer from) {
      return String.valueOf(from);
    }
  }

  public void testTransformWith_nullFriendlyTransform() {
    List<Integer> input = asList(1, 2, null, 3);
    Iterable<String> result = FluentIterable.from(input).transform(new StringValueOfFunction());

    assertEquals(asList("1", "2", "null", "3"), Lists.newArrayList(result));
  }

  private static final class RepeatedStringValueOfFunction
      implements Function<Integer, List {
    @Override
    public List<String> apply(Integer from) {
      String value = String.valueOf(from);
      return ImmutableList.of(value, value);
    }
  }

  public void testTransformAndConcat() {
    List<Integer> input = asList(1, 2, 3);
    Iterable<String> result =
        FluentIterable.from(input).transformAndConcat(new RepeatedStringValueOfFunction());
    assertEquals(asList("1", "1", "2", "2", "3", "3"), Lists.newArrayList(result));
  }

  private static final class RepeatedStringValueOfWildcardFunction
      implements Function<Integer, List {
    @Override
    public List<String> apply(Integer from) {
      String value = String.valueOf(from);
      return ImmutableList.of(value, value);
    }
  }

  public void testTransformAndConcat_wildcardFunctionGenerics() {
    List<Integer> input = asList(1, 2, 3);
    FluentIterable<String> unused =
        FluentIterable.from(input).transformAndConcat(new RepeatedStringValueOfWildcardFunction());
  }

  public void testFirst_list() {
    List<String> list = Lists.newArrayList("a", "b", "c");
    assertThat(FluentIterable.from(list).first()).hasValue("a");
  }

  public void testFirst_null() {
    List<String> list = Lists.newArrayList(null, "a", "b");
    try {
      FluentIterable.from(list).first();
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testFirst_emptyList() {
    List<String> list = Collections.emptyList();
    assertThat(FluentIterable.from(list).first()).isAbsent();
  }

  public void testFirst_sortedSet() {
    SortedSet<String> sortedSet = ImmutableSortedSet.of("b", "c", "a");
    assertThat(FluentIterable.from(sortedSet).first()).hasValue("a");
  }

  public void testFirst_emptySortedSet() {
    SortedSet<String> sortedSet = ImmutableSortedSet.of();
    assertThat(FluentIterable.from(sortedSet).first()).isAbsent();
  }

  public void testFirst_iterable() {
    Set<String> set = ImmutableSet.of("a", "b", "c");
    assertThat(FluentIterable.from(set).first()).hasValue("a");
  }

  public void testFirst_emptyIterable() {
    Set<String> set = Sets.newHashSet();
    assertThat(FluentIterable.from(set).first()).isAbsent();
  }

  public void testLast_list() {
    List<String> list = Lists.newArrayList("a", "b", "c");
    assertThat(FluentIterable.from(list).last()).hasValue("c");
  }

  public void testLast_null() {
    List<String> list = Lists.newArrayList("a", "b", null);
    try {
      FluentIterable.from(list).last();
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testLast_emptyList() {
    List<String> list = Collections.emptyList();
    assertThat(FluentIterable.from(list).last()).isAbsent();
  }

  public void testLast_sortedSet() {
    SortedSet<String> sortedSet = ImmutableSortedSet.of("b", "c", "a");
    assertThat(FluentIterable.from(sortedSet).last()).hasValue("c");
  }

  public void testLast_emptySortedSet() {
    SortedSet<String> sortedSet = ImmutableSortedSet.of();
    assertThat(FluentIterable.from(sortedSet).last()).isAbsent();
  }

  public void testLast_iterable() {
    Set<String> set = ImmutableSet.of("a", "b", "c");
    assertThat(FluentIterable.from(set).last()).hasValue("c");
  }

  public void testLast_emptyIterable() {
    Set<String> set = Sets.newHashSet();
    assertThat(FluentIterable.from(set).last()).isAbsent();
  }

  public void testSkip_simple() {
    Collection<String> set = ImmutableSet.of("a", "b", "c", "d", "e");
    assertEquals(Lists.newArrayList("c", "d", "e"),
        Lists.newArrayList(FluentIterable.from(set).skip(2)));
    assertEquals("[c, d, e]", FluentIterable.from(set).skip(2).toString());
  }

  public void testSkip_simpleList() {
    Collection<String> list = Lists.newArrayList("a", "b", "c", "d", "e");
    assertEquals(Lists.newArrayList("c", "d", "e"),
        Lists.newArrayList(FluentIterable.from(list).skip(2)));
    assertEquals("[c, d, e]", FluentIterable.from(list).skip(2).toString());
  }

  public void testSkip_pastEnd() {
    Collection<String> set = ImmutableSet.of("a", "b");
    assertEquals(Collections.emptyList(), Lists.newArrayList(FluentIterable.from(set).skip(20)));
  }

  public void testSkip_pastEndList() {
    Collection<String> list = Lists.newArrayList("a", "b");
    assertEquals(Collections.emptyList(), Lists.newArrayList(FluentIterable.from(list).skip(20)));
  }

  public void testSkip_skipNone() {
    Collection<String> set = ImmutableSet.of("a", "b");
    assertEquals(Lists.newArrayList("a", "b"),
        Lists.newArrayList(FluentIterable.from(set).skip(0)));
  }

  public void testSkip_skipNoneList() {
    Collection<String> list = Lists.newArrayList("a", "b");
    assertEquals(Lists.newArrayList("a", "b"),
        Lists.newArrayList(FluentIterable.from(list).skip(0)));
  }

  public void testSkip_iterator() throws Exception {
    new IteratorTester<Integer>(5, IteratorFeature.MODIFIABLE, Lists.newArrayList(2, 3),
        IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override protected Iterator<Integer> newTargetIterator() {
        Collection<Integer> collection = Sets.newLinkedHashSet();
        Collections.addAll(collection, 1, 2, 3);
        return FluentIterable.from(collection).skip(1).iterator();
      }
    }.test();
  }

  public void testSkip_iteratorList() throws Exception {
    new IteratorTester<Integer>(5, IteratorFeature.MODIFIABLE, Lists.newArrayList(2, 3),
        IteratorTester.KnownOrder.KNOWN_ORDER) {
      @Override protected Iterator<Integer> newTargetIterator() {
        return FluentIterable.from(Lists.newArrayList(1, 2, 3)).skip(1).iterator();
      }
    }.test();
  }

  public void testSkip_nonStructurallyModifiedList() throws Exception {
    List<String> list = Lists.newArrayList("a", "b", "c");
    FluentIterable<String> tail = FluentIterable.from(list).skip(1);
    Iterator<String> tailIterator = tail.iterator();
    list.set(2, "c2");
    assertEquals("b", tailIterator.next());
    assertEquals("c2", tailIterator.next());
    assertFalse(tailIterator.hasNext());
  }

  public void testSkip_structurallyModifiedSkipSome() throws Exception {
    Collection<String> set = Sets.newLinkedHashSet();
    Collections.addAll(set, "a", "b", "c");
    FluentIterable<String> tail = FluentIterable.from(set).skip(1);
    set.remove("b");
    set.addAll(Lists.newArrayList("X", "Y", "Z"));
    assertThat(tail).containsExactly("c", "X", "Y", "Z").inOrder();
  }

  public void testSkip_structurallyModifiedSkipSomeList() throws Exception {
    List<String> list = Lists.newArrayList("a", "b", "c");
    FluentIterable<String> tail = FluentIterable.from(list).skip(1);
    list.subList(1, 3).clear();
    list.addAll(0, Lists.newArrayList("X", "Y", "Z"));
    assertThat(tail).containsExactly("Y", "Z", "a").inOrder();
  }

  public void testSkip_structurallyModifiedSkipAll() throws Exception {
    Collection<String> set = Sets.newLinkedHashSet();
    Collections.addAll(set, "a", "b", "c");
    FluentIterable<String> tail = FluentIterable.from(set).skip(2);
    set.remove("a");
    set.remove("b");
    assertFalse(tail.iterator().hasNext());
  }

  public void testSkip_structurallyModifiedSkipAllList() throws Exception {
    List<String> list = Lists.newArrayList("a", "b", "c");
    FluentIterable<String> tail = FluentIterable.from(list).skip(2);
    list.subList(0, 2).clear();
    assertThat(tail).isEmpty();
  }

  public void testSkip_illegalArgument() {
    try {
      FluentIterable.from(asList("a", "b", "c")).skip(-1);
      fail("Skipping negative number of elements should throw IllegalArgumentException.");
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testLimit() {
    Iterable<String> iterable = Lists.newArrayList("foo", "bar", "baz");
    FluentIterable<String> limited = FluentIterable.from(iterable).limit(2);

    assertEquals(ImmutableList.of("foo", "bar"), Lists.newArrayList(limited));
    assertCanIterateAgain(limited);
    assertEquals("[foo, bar]", limited.toString());
  }

  public void testLimit_illegalArgument() {
    try {
      FluentIterable<String> unused =
          FluentIterable.from(Lists.newArrayList("a", "b", "c")).limit(-1);
      fail("Passing negative number to limit(...) method should throw IllegalArgumentException");
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testIsEmpty() {
    assertTrue(FluentIterable.<String>from(Collections.emptyList()).isEmpty());
    assertFalse(FluentIterable.<String>from(Lists.newArrayList("foo")).isEmpty());
  }

  public void testToList() {
    assertEquals(Lists.newArrayList(1, 2, 3, 4), fluent(1, 2, 3, 4).toList());
  }

  public void testToList_empty() {
    assertTrue(fluent().toList().isEmpty());
  }

  public void testToSortedList_withComparator() {
    assertEquals(Lists.newArrayList(4, 3, 2, 1),
        fluent(4, 1, 3, 2).toSortedList(Ordering.<Integer>natural().reverse()));
  }

  public void testToSortedList_withDuplicates() {
    assertEquals(Lists.newArrayList(4, 3, 1, 1),
        fluent(1, 4, 1, 3).toSortedList(Ordering.<Integer>natural().reverse()));
  }

  public void testToSet() {
    assertThat(fluent(1, 2, 3, 4).toSet()).containsExactly(1, 2, 3, 4).inOrder();
  }

  public void testToSet_removeDuplicates() {
    assertThat(fluent(1, 2, 1, 2).toSet()).containsExactly(1, 2).inOrder();
  }

  public void testToSet_empty() {
    assertTrue(fluent().toSet().isEmpty());
  }

  public void testToSortedSet() {
    assertThat(fluent(1, 4, 2, 3).toSortedSet(Ordering.<Integer>natural().reverse()))
        .containsExactly(4, 3, 2, 1).inOrder();
  }

  public void testToSortedSet_removeDuplicates() {
    assertThat(fluent(1, 4, 1, 3).toSortedSet(Ordering.<Integer>natural().reverse()))
        .containsExactly(4, 3, 1).inOrder();
  }

  public void testToMultiset() {
    assertThat(fluent(1, 2, 1, 3, 2, 4).toMultiset()).containsExactly(1, 1, 2, 2, 3, 4).inOrder();
  }

  public void testToMultiset_empty() {
    assertThat(fluent().toMultiset()).isEmpty();
  }

  public void testToMap() {
    assertThat(fluent(1, 2, 3).toMap(Functions.toStringFunction()).entrySet())
        .containsExactly(
            Maps.immutableEntry(1, "1"),
            Maps.immutableEntry(2, "2"),
            Maps.immutableEntry(3, "3")).inOrder();
  }

  public void testToMap_nullKey() {
    try {
      fluent(1, null, 2).toMap(Functions.constant("foo"));
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testToMap_nullValue() {
    try {
      fluent(1, 2, 3).toMap(Functions.constant(null));
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testIndex() {
    ImmutableListMultimap<Integer, String> expected =
        ImmutableListMultimap.<Integer, String>builder()
            .putAll(3, "one", "two")
            .put(5, "three")
            .put(4, "four")
            .build();
    ImmutableListMultimap<Integer, String> index =
        FluentIterable.from(asList("one", "two", "three", "four")).index(
            new Function<String, Integer>() {
              @Override
              public Integer apply(String input) {
                return input.length();
              }
            });
    assertEquals(expected, index);
  }

  public void testIndex_nullKey() {
    try {
      ImmutableListMultimap<Object, Integer> unused =
          fluent(1, 2, 3).index(Functions.constant(null));
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testIndex_nullValue() {
    try {
      ImmutableListMultimap<String, Integer> unused =
          fluent(1, null, 2).index(Functions.constant("foo"));
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testUniqueIndex() {
    ImmutableMap<Integer, String> expected =
        ImmutableMap.of(3, "two", 5, "three", 4, "four");
    ImmutableMap<Integer, String> index =
        FluentIterable.from(asList("two", "three", "four")).uniqueIndex(
            new Function<String, Integer>() {
              @Override
              public Integer apply(String input) {
                return input.length();
              }
            });
    assertEquals(expected, index);
  }

  public void testUniqueIndex_duplicateKey() {
    try {
      ImmutableMap<Integer, String> unused =
          FluentIterable.from(asList("one", "two", "three", "four"))
              .uniqueIndex(
                  new Function<String, Integer>() {
                    @Override
                    public Integer apply(String input) {
                      return input.length();
                    }
                  });
      fail();
    } catch (IllegalArgumentException expected) {
    }
  }

  public void testUniqueIndex_nullKey() {
    try {
      fluent(1, 2, 3).uniqueIndex(Functions.constant(null));
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testUniqueIndex_nullValue() {
    try {
      ImmutableMap<Object, Integer> unused =
          fluent(1, null, 2)
              .uniqueIndex(
                  new Function<Integer, Object>() {
                    @Override
                    public Object apply(@Nullable Integer input) {
                      return String.valueOf(input);
                    }
                  });
      fail();
    } catch (NullPointerException expected) {
    }
  }

  public void testCopyInto_List() {
    assertThat(fluent(1, 3, 5).copyInto(Lists.newArrayList(1, 2)))
        .containsExactly(1, 2, 1, 3, 5).inOrder();
  }

  public void testCopyInto_Set() {
    assertThat(fluent(1, 3, 5).copyInto(Sets.newHashSet(1, 2)))
        .containsExactly(1, 2, 3, 5);
  }

  public void testCopyInto_SetAllDuplicates() {
    assertThat(fluent(1, 3, 5).copyInto(Sets.newHashSet(1, 2, 3, 5)))
        .containsExactly(1, 2, 3, 5);
  }

  public void testCopyInto_NonCollection() {
    final ArrayList<Integer> list = Lists.newArrayList(1, 2, 3);

    final ArrayList<Integer> iterList = Lists.newArrayList(9, 8, 7);
    Iterable<Integer> iterable = new Iterable() {
      @Override
      public Iterator<Integer> iterator() {
        return iterList.iterator();
      }
    };

    assertThat(FluentIterable.from(iterable).copyInto(list))
        .containsExactly(1, 2, 3, 9, 8, 7).inOrder();
  }

  public void testJoin() {
    assertEquals("2,1,3,4", fluent(2, 1, 3, 4).join(Joiner.on(",")));
  }

  public void testJoin_empty() {
    assertEquals("", fluent().join(Joiner.on(",")));
  }

  public void testGet() {
    assertEquals("a", FluentIterable
        .from(Lists.newArrayList("a", "b", "c")).get(0));
    assertEquals("b", FluentIterable
        .from(Lists.newArrayList("a", "b", "c")).get(1));
    assertEquals("c", FluentIterable
        .from(Lists.newArrayList("a", "b", "c")).get(2));
  }

  public void testGet_outOfBounds() {
    try {
      FluentIterable.from(Lists.newArrayList("a", "b", "c")).get(-1);
      fail();
    } catch (IndexOutOfBoundsException expected) {
    }

    try {
      FluentIterable.from(Lists.newArrayList("a", "b", "c")).get(3);
      fail();
    } catch (IndexOutOfBoundsException expected) {
    }
  }

  private static void assertCanIterateAgain(Iterable<?> iterable) {
    for (Object unused : iterable) {
      // do nothing
    }
  }

  private static FluentIterable<Integer> fluent(Integer... elements) {
    return FluentIterable.from(Lists.newArrayList(elements));
  }

  private static Iterable<String> iterable(String... elements) {
    final List<String> list = asList(elements);
    return new Iterable<String>() {
      @Override
      public Iterator<String> iterator() {
        return list.iterator();
      }
    };
  }
}




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