/*
* 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 under the License.
*/
package org.apache.flink.python.api.streaming.data;
import org.junit.Assert;
import org.junit.Test;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
public class SingleElementPushBackIteratorTest {
@Test
public void testPushBackIterator() {
Collection<Integer> init = new ArrayList<>();
init.add(1);
init.add(2);
init.add(4);
init.add(5);
SingleElementPushBackIterator<Integer> iterator = new SingleElementPushBackIterator<>(init.iterator());
Assert.assertTrue(iterator.hasNext());
Assert.assertEquals(1, (int) iterator.next());
Assert.assertTrue(iterator.hasNext());
Assert.assertEquals(2, (int) iterator.next());
Assert.assertTrue(iterator.hasNext());
iterator.pushBack(3);
Assert.assertTrue(iterator.hasNext());
Assert.assertEquals(3, (int) iterator.next());
Assert.assertTrue(iterator.hasNext());
Assert.assertEquals(4, (int) iterator.next());
Assert.assertTrue(iterator.hasNext());
Assert.assertEquals(5, (int) iterator.next());
Assert.assertFalse(iterator.hasNext());
iterator.pushBack(6);
Assert.assertTrue(iterator.hasNext());
Assert.assertEquals(6, (int) iterator.next());
Assert.assertFalse(iterator.hasNext());
}
@Test
public void testSingleElementLimitation() {
Collection<Integer> init = Collections.emptyList();
SingleElementPushBackIterator<Integer> iterator = new SingleElementPushBackIterator<>(init.iterator());
Assert.assertFalse(iterator.hasNext());
iterator.pushBack(1);
try {
iterator.pushBack(2);
Assert.fail("Multiple elements could be pushed back.");
} catch (IllegalStateException ignored) {
// expected
}
}
}