DistinctUntilChanged.cs 1.9 KB

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  1. // Licensed to the .NET Foundation under one or more agreements.
  2. // The .NET Foundation licenses this file to you under the MIT License.
  3. // See the LICENSE file in the project root for more information.
  4. using System;
  5. using System.Collections.Generic;
  6. using System.Linq;
  7. using Xunit;
  8. namespace Tests
  9. {
  10. public class DistinctUntilChanged : Tests
  11. {
  12. [Fact]
  13. public void DistinctUntilChanged_Arguments()
  14. {
  15. AssertThrows<ArgumentNullException>(() => EnumerableEx.DistinctUntilChanged<int>(null));
  16. AssertThrows<ArgumentNullException>(() => EnumerableEx.DistinctUntilChanged<int>(null, EqualityComparer<int>.Default));
  17. AssertThrows<ArgumentNullException>(() => EnumerableEx.DistinctUntilChanged<int>([1], null));
  18. AssertThrows<ArgumentNullException>(() => EnumerableEx.DistinctUntilChanged<int, int>(null, _ => _));
  19. AssertThrows<ArgumentNullException>(() => EnumerableEx.DistinctUntilChanged<int, int>([1], null));
  20. AssertThrows<ArgumentNullException>(() => EnumerableEx.DistinctUntilChanged<int, int>(null, _ => _, EqualityComparer<int>.Default));
  21. AssertThrows<ArgumentNullException>(() => EnumerableEx.DistinctUntilChanged<int, int>([1], null, EqualityComparer<int>.Default));
  22. AssertThrows<ArgumentNullException>(() => EnumerableEx.DistinctUntilChanged<int, int>([1], _ => _, null));
  23. }
  24. [Fact]
  25. public void DistinctUntilChanged1()
  26. {
  27. var res = new[] { 1, 2, 2, 3, 3, 3, 2, 2, 1 }.DistinctUntilChanged().ToList();
  28. Assert.True(Enumerable.SequenceEqual(res, [1, 2, 3, 2, 1]));
  29. }
  30. [Fact]
  31. public void DistinctUntilChanged2()
  32. {
  33. var res = new[] { 1, 1, 2, 3, 4, 5, 5, 6, 7 }.DistinctUntilChanged(x => x / 2).ToList();
  34. Assert.True(Enumerable.SequenceEqual(res, [1, 2, 4, 6]));
  35. }
  36. }
  37. }