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 * 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   *
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 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
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package org.apache.james.util;

import static org.assertj.core.api.Assertions.assertThat;
import static org.assertj.core.api.Assertions.assertThatNullPointerException;

import org.junit.jupiter.api.Test;

import com.google.common.collect.ImmutableList;

public class IteratorWrapperTest {

    @Test
    void getEntriesSeenShouldReturnEmptyWhenNotConsumed() {
        ImmutableList<Integer> originalData = ImmutableList.of(1, 2, 3);
        IteratorWrapper<Integer> integerIteratorWrapper = new IteratorWrapper<>(originalData.iterator());

        assertThat(integerIteratorWrapper.getEntriesSeen()).isEmpty();
    }

    @Test
    void getEntriesSeenShouldReturnViewOfConsumedData() {
        ImmutableList<Integer> originalData = ImmutableList.of(1, 2, 3);
        IteratorWrapper<Integer> integerIteratorWrapper = new IteratorWrapper<>(originalData.iterator());

        consume(integerIteratorWrapper);

        assertThat(integerIteratorWrapper.getEntriesSeen())
            .containsExactlyElementsOf(originalData);
    }

    @Test
    void getEntriesSeenShouldReturnViewOfConsumedDataWhenPartiallyConsumed() {
        ImmutableList<Integer> originalData = ImmutableList.of(1, 2, 3);
        IteratorWrapper<Integer> integerIteratorWrapper = new IteratorWrapper<>(originalData.iterator());

        integerIteratorWrapper.next();
        integerIteratorWrapper.next();

        assertThat(integerIteratorWrapper.getEntriesSeen())
            .containsOnly(1, 2);
    }

    @Test
    void getEntriesSeenShouldReturnEmptyWhenSuppliedEmpty() {
        ImmutableList<Integer> originalData = ImmutableList.of();
        IteratorWrapper<Integer> integerIteratorWrapper = new IteratorWrapper<>(originalData.iterator());

        consume(integerIteratorWrapper);

        assertThat(integerIteratorWrapper.getEntriesSeen())
            .containsExactlyElementsOf(originalData);
    }

    @Test
    void constructorShouldThrowOnNull() {
        assertThatNullPointerException()
            .isThrownBy(() -> new IteratorWrapper<Integer>(null));
    }

    private void consume(IteratorWrapper<Integer> integerIteratorWrapper) {
        while (integerIteratorWrapper.hasNext()) {
            integerIteratorWrapper.next();
        }
    }

}
