// 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 DistinctUntilChanged : AsyncEnumerableExTests { [Fact] public void DistinctUntilChanged_Null() { AssertThrows(() => AsyncEnumerableEx.DistinctUntilChanged(default(IAsyncEnumerable))); AssertThrows(() => AsyncEnumerableEx.DistinctUntilChanged(default, EqualityComparer.Default)); AssertThrows(() => AsyncEnumerableEx.DistinctUntilChanged(Return42, default)); AssertThrows(() => AsyncEnumerableEx.DistinctUntilChanged(default(IAsyncEnumerable), x => x)); AssertThrows(() => AsyncEnumerableEx.DistinctUntilChanged(Return42, default(Func))); AssertThrows(() => AsyncEnumerableEx.DistinctUntilChanged(default(IAsyncEnumerable), x => x, EqualityComparer.Default)); AssertThrows(() => AsyncEnumerableEx.DistinctUntilChanged(Return42, default(Func), EqualityComparer.Default)); AssertThrows(() => AsyncEnumerableEx.DistinctUntilChanged(Return42, x => x, default)); } [Fact] public void DistinctUntilChanged1() { var xs = new[] { 1, 2, 2, 3, 4, 4, 4, 4, 5, 6, 6, 7, 3, 2, 2, 1, 1 }.ToAsyncEnumerable().DistinctUntilChanged(); var e = xs.GetAsyncEnumerator(); HasNext(e, 1); HasNext(e, 2); HasNext(e, 3); HasNext(e, 4); HasNext(e, 5); HasNext(e, 6); HasNext(e, 7); HasNext(e, 3); HasNext(e, 2); HasNext(e, 1); NoNext(e); } [Fact] public void DistinctUntilChanged2() { var xs = new[] { 1, 2, 3, 4, 3, 5, 2 }.ToAsyncEnumerable().DistinctUntilChanged(x => (x + 1) / 2); var e = xs.GetAsyncEnumerator(); HasNext(e, 1); HasNext(e, 3); HasNext(e, 5); HasNext(e, 2); NoNext(e); } [Fact] public void DistinctUntilChanged3() { var ex = new Exception("Bang!"); var xs = new[] { 1, 2, 3, 4, 3, 5, 2 }.ToAsyncEnumerable().DistinctUntilChanged(x => { if (x == 4) throw ex; return x; }); var e = xs.GetAsyncEnumerator(); HasNext(e, 1); HasNext(e, 2); HasNext(e, 3); AssertThrows(() => e.MoveNextAsync().Wait(WaitTimeoutMs), SingleInnerExceptionMatches(ex)); } [Fact] public async Task DistinctUntilChanged4() { var xs = new[] { 1, 2, 2, 3, 4, 4, 4, 4, 5, 6, 6, 7, 3, 2, 2, 1, 1 }.ToAsyncEnumerable().DistinctUntilChanged(); await SequenceIdentity(xs); } [Fact] public async Task DistinctUntilChanged5() { var xs = new[] { 1, 2, 3, 4, 3, 5, 2 }.ToAsyncEnumerable().DistinctUntilChanged(x => (x + 1) / 2); await SequenceIdentity(xs); } } }