/*
 * Licensed to Crate.io GmbH ("Crate") under one or more contributor
 * license agreements.  See the NOTICE file distributed with this work for
 * additional information regarding copyright ownership.  Crate 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.
 *
 * However, if you have executed another commercial license agreement
 * with Crate these terms will supersede the license and you may use the
 * software solely pursuant to the terms of the relevant commercial agreement.
 */

package io.crate.common.concurrent;

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

import java.util.Arrays;
import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.TimeUnit;

import org.junit.Test;

public class CompletableFuturesTest {

    @Test
    public void testAllAsListFailurePropagation() {
        CompletableFuture<Integer> f1 = new CompletableFuture<>();
        CompletableFuture<Integer> f2 = new CompletableFuture<>();
        CompletableFuture<List<Integer>> all = CompletableFutures.allAsList(Arrays.asList(f1, f2));

        f1.completeExceptionally(new IllegalStateException("dummy"));
        assertThat(all.isDone())
            .as("future must wait for all subFutures")
            .isFalse();

        f2.complete(2);
        assertThatThrownBy(() -> all.get(10, TimeUnit.SECONDS))
            .isExactlyInstanceOf(ExecutionException.class)
            .hasCauseInstanceOf(IllegalStateException.class);
    }

    @Test
    public void testAllAsListResultContainsListOfResults() throws Exception {
        CompletableFuture<Integer> f1 = new CompletableFuture<>();
        CompletableFuture<Integer> f2 = new CompletableFuture<>();
        CompletableFuture<List<Integer>> all = CompletableFutures.allAsList(Arrays.asList(f1, f2));

        f1.complete(10);
        f2.complete(20);

        assertThat(all.get(10, TimeUnit.SECONDS)).containsExactly(10, 20);
    }

    @Test
    public void testSupplyAsyncReturnsFailedFutureOnException() {
        Executor rejectingExecutor = command -> {
            throw new RejectedExecutionException("rejected");
        };
        CompletableFuture<Object> future = CompletableFutures.supplyAsync(() -> null, rejectingExecutor);
        assertThat(future.isCompletedExceptionally()).isTrue();
    }
}
