/*
 * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
 * or more contributor license agreements. Licensed under the "Elastic License
 * 2.0", the "GNU Affero General Public License v3.0 only", and the "Server Side
 * Public License v 1"; you may not use this file except in compliance with, at
 * your election, the "Elastic License 2.0", the "GNU Affero General Public
 * License v3.0 only", or the "Server Side Public License, v 1".
 */

package org.elasticsearch.common.util;

import org.elasticsearch.test.ESTestCase;

import java.util.Map;

import static org.hamcrest.Matchers.equalTo;
import static org.hamcrest.Matchers.not;
import static org.hamcrest.Matchers.sameInstance;

public class CopyOnFirstWriteMapTests extends ESTestCase {

    public void testShouldNotCopyIfThereWereNoUpdates() {
        var source = Map.of("key", "value");
        var copyOnFirstWrite = new CopyOnFirstWriteMap<>(source);
        var copy = copyOnFirstWrite.toImmutableMap();

        assertThat(copy, sameInstance(source));
        assertThat(copy, equalTo(source));
    }

    public void testShouldNotCopyWhenPuttingTheSameValue() {
        var source = Map.of("key", "value");
        var copyOnFirstWrite = new CopyOnFirstWriteMap<>(source);
        copyOnFirstWrite.put("key", "value");
        var copy = copyOnFirstWrite.toImmutableMap();

        assertThat(copy, sameInstance(source));
        assertThat(copy, equalTo(source));
    }

    public void testShouldBeUpdatable() {
        var source = Map.of("key", "value");
        var copyOnFirstWrite = new CopyOnFirstWriteMap<>(source);
        copyOnFirstWrite.put("key", "new_value");
        var copy = copyOnFirstWrite.toImmutableMap();

        assertThat(copy, not(sameInstance(source)));
        assertThat(copy, equalTo(Map.of("key", "new_value")));
    }
}