test/com/google/common/collect/testing/MinimalIterableTest.java

/*
 * Copyright (C) 2009 Google Inc.
 *
 * 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 junit.framework.TestCase;

import java.util.Collections;
import java.util.Iterator;
import java.util.NoSuchElementException;

/**
 * Unit test for {@link MinimalIterable}.
 *
 * @author Kevin Bourrillion
 */
public class MinimalIterableTest extends TestCase {

  public void testOf_empty() {
    Iterable<String> iterable = MinimalIterable.<String>of();
    Iterator<String> iterator = iterable.iterator();
    assertFalse(iterator.hasNext());
    try {
      iterator.next();
      fail();
    } catch (NoSuchElementException expected) {
    }
    try {
      iterable.iterator();
      fail();
    } catch (IllegalStateException expected) {
    }
  }

  public void testOf_one() {
    Iterable<String> iterable = MinimalIterable.of("a");
    Iterator<String> iterator = iterable.iterator();
    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    assertFalse(iterator.hasNext());
    try {
      iterator.next();
      fail();
    } catch (NoSuchElementException expected) {
    }
    try {
      iterable.iterator();
      fail();
    } catch (IllegalStateException expected) {
    }
  }

  public void testFrom_empty() {
    Iterable<String> iterable
        = MinimalIterable.from(Collections.<String>emptySet());
    Iterator<String> iterator = iterable.iterator();
    assertFalse(iterator.hasNext());
    try {
      iterator.next();
      fail();
    } catch (NoSuchElementException expected) {
    }
    try {
      iterable.iterator();
      fail();
    } catch (IllegalStateException expected) {
    }
  }

  public void testFrom_one() {
    Iterable<String> iterable
        = MinimalIterable.from(Collections.singleton("a"));
    Iterator<String> iterator = iterable.iterator();
    assertTrue(iterator.hasNext());
    assertEquals("a", iterator.next());
    try {
      iterator.remove();
      fail();
    } catch (UnsupportedOperationException expected) {
    }
    assertFalse(iterator.hasNext());
    try {
      iterator.next();
      fail();
    } catch (NoSuchElementException expected) {
    }
    try {
      iterable.iterator();
      fail();
    } catch (IllegalStateException expected) {
    }
  }
}