// Licensed to the .NET Foundation under one or more agreements. // The .NET Foundation licenses this file to you under the Apache 2.0 License. // See the LICENSE file in the project root for more information. using System; using System.Collections.Generic; using System.Linq; using System.Threading.Tasks; using Xunit; namespace Tests { public class Distinct : AsyncEnumerableTests { [Fact] public void Distinct_Null() { AssertThrows(() => AsyncEnumerable.Distinct(default)); AssertThrows(() => AsyncEnumerable.Distinct(default, EqualityComparer.Default)); AssertThrows(() => AsyncEnumerable.Distinct(Return42, default)); } [Fact] public void Distinct1() { var xs = new[] { 1, 2, 1, 3, 5, 2, 1, 4 }.ToAsyncEnumerable().Distinct(); var e = xs.GetAsyncEnumerator(); HasNext(e, 1); HasNext(e, 2); HasNext(e, 3); HasNext(e, 5); HasNext(e, 4); NoNext(e); } [Fact] public void Distinct2() { var xs = new[] { 1, -2, -1, 3, 5, 2, 1, 4 }.ToAsyncEnumerable().Distinct(new Eq()); var e = xs.GetAsyncEnumerator(); HasNext(e, 1); HasNext(e, -2); HasNext(e, 3); HasNext(e, 5); HasNext(e, 4); NoNext(e); } [Fact] public async Task Distinct3() { var xs = new[] { 1, 2, 1, 3, 5, 2, 1, 4 }.ToAsyncEnumerable().Distinct(); var res = new[] { 1, 2, 3, 5, 4 }; Assert.True(res.SequenceEqual(await xs.ToArray())); } [Fact] public async Task Distinct4() { var xs = new[] { 1, 2, 1, 3, 5, 2, 1, 4 }.ToAsyncEnumerable().Distinct(); var res = new List { 1, 2, 3, 5, 4 }; Assert.True(res.SequenceEqual(await xs.ToList())); } [Fact] public async Task Distinct5() { var xs = new[] { 1, 2, 1, 3, 5, 2, 1, 4 }.ToAsyncEnumerable().Distinct(); Assert.Equal(5, await xs.Count()); } [Fact] public async Task Distinct10() { var xs = new[] { 1, 2, 1, 3, 5, 2, 1, 4 }.ToAsyncEnumerable().Distinct(); await SequenceIdentity(xs); } [Fact] public void Distinct12() { var xs = AsyncEnumerable.Empty().Distinct(); var e = xs.GetAsyncEnumerator(); NoNext(e); } private sealed class Eq : IEqualityComparer { public bool Equals(int x, int y) { return EqualityComparer.Default.Equals(Math.Abs(x), Math.Abs(y)); } public int GetHashCode(int obj) { return EqualityComparer.Default.GetHashCode(Math.Abs(obj)); } } } }