feat: support .NET 8.0 | Add new methods for IRandom (#387)

- #381 Add new methods for `IRandom`: - [`GetItems`](https://learn.microsoft.com/en-us/dotnet/api/system.random.getitems?view=net-8.0) - [`Shuffle`](https://learn.microsoft.com/en-us/dotnet/api/system.random.shuffle?view=net-8.0)
Testably · Aug 24, 2023 · b5644f6 · b5644f6
1 parent 7f490bf
commit b5644f6
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Showing 5 changed files with 277 additions and 2 deletions.
diff --git a/Source/Testably.Abstractions.Interface/Helpers/RandomWrapper.cs b/Source/Testably.Abstractions.Interface/Helpers/RandomWrapper.cs
@@ -21,6 +21,20 @@ public RandomWrapper(Random instance)
 
 	#region IRandom Members
 
+#if FEATURE_RANDOM_ITEMS
+	/// <inheritdoc cref="IRandom.GetItems{T}(ReadOnlySpan{T}, Span{T})" />
+	public void GetItems<T>(ReadOnlySpan<T> choices, Span<T> destination)
+		=> _instance.GetItems(choices, destination);
+
+	/// <inheritdoc cref="IRandom.GetItems{T}(T[], int)" />
+	public T[] GetItems<T>(T[] choices, int length)
+		=> _instance.GetItems(choices, length);
+
+	/// <inheritdoc cref="IRandom.GetItems{T}(ReadOnlySpan{T}, int)" />
+	public T[] GetItems<T>(ReadOnlySpan<T> choices, int length)
+		=> _instance.GetItems(choices, length);
+#endif
+
 	/// <inheritdoc cref="IRandom.Next()" />
 	public int Next()
 		=> _instance.Next();
@@ -65,5 +79,15 @@ public float NextSingle()
 		=> _instance.NextSingle();
 #endif
 
+#if FEATURE_RANDOM_ITEMS
+	/// <inheritdoc cref="IRandom.Shuffle{T}(T[])" />
+	public void Shuffle<T>(T[] values)
+		=> _instance.Shuffle(values);
+
+	/// <inheritdoc cref="IRandom.Shuffle{T}(Span{T})" />
+	public void Shuffle<T>(Span<T> values)
+		=> _instance.Shuffle(values);
+#endif
+
 	#endregion
 }
diff --git a/Source/Testably.Abstractions.Interface/RandomSystem/IRandom.cs b/Source/Testably.Abstractions.Interface/RandomSystem/IRandom.cs
@@ -7,6 +7,17 @@ namespace Testably.Abstractions.RandomSystem;
 /// </summary>
 public interface IRandom
 {
+#if FEATURE_RANDOM_ITEMS
+	/// <inheritdoc cref="Random.GetItems{T}(ReadOnlySpan{T}, Span{T})" />
+	void GetItems<T>(ReadOnlySpan<T> choices, Span<T> destination);
+
+	/// <inheritdoc cref="Random.GetItems{T}(T[], int)" />
+	T[] GetItems<T>(T[] choices, int length);
+
+	/// <inheritdoc cref="Random.GetItems{T}(ReadOnlySpan{T}, int)" />
+	T[] GetItems<T>(ReadOnlySpan<T> choices, int length);
+#endif
+
 	/// <inheritdoc cref="Random.Next()" />
 	int Next();
 
@@ -40,4 +51,12 @@ public interface IRandom
 	/// <inheritdoc cref="Random.NextSingle()" />
 	float NextSingle();
 #endif
+
+#if FEATURE_RANDOM_ITEMS
+	/// <inheritdoc cref="Random.Shuffle{T}(T[])" />
+	void Shuffle<T>(T[] values);
+
+	/// <inheritdoc cref="Random.Shuffle{T}(Span{T})" />
+	void Shuffle<T>(Span<T> values);
+#endif
 }
diff --git a/Source/Testably.Abstractions.Testing/Helpers/ExceptionFactory.cs b/Source/Testably.Abstractions.Testing/Helpers/ExceptionFactory.cs
@@ -190,6 +190,14 @@ internal static IOException SeekBackwardNotPossibleInAppendMode()
 			"Unable seek backward to overwrite data that previously existed in a file opened in Append mode.",
 			-2146232800);
 
+	internal static ArgumentException SpanMayNotBeEmpty(string paramName)
+		=> new("Span may not be empty.", paramName)
+		{
+#if FEATURE_EXCEPTION_HRESULT
+			HResult = -2147024809
+#endif
+		};
+
 	internal static NotSupportedException StreamDoesNotSupportReading()
 		=> new("Stream does not support reading.")
 		{

diff --git a/Source/Testably.Abstractions.Testing/RandomSystem/RandomMock.cs b/Source/Testably.Abstractions.Testing/RandomSystem/RandomMock.cs
@@ -62,6 +62,39 @@ public RandomMock(
 
 	#region IRandom Members
 
+#if FEATURE_RANDOM_ITEMS
+	/// <inheritdoc cref="IRandom.GetItems{T}(ReadOnlySpan{T}, Span{T})" />
+	public void GetItems<T>(ReadOnlySpan<T> choices, Span<T> destination)
+	{
+		if (choices.IsEmpty)
+		{
+			throw ExceptionFactory.SpanMayNotBeEmpty(nameof(choices));
+		}
+
+		for (int i = 0; i < destination.Length; i++)
+		{
+			destination[i] = choices[Next(choices.Length)];
+		}
+	}
+
+	/// <inheritdoc cref="IRandom.GetItems{T}(T[], int)" />
+	public T[] GetItems<T>(T[] choices, int length)
+	{
+		ArgumentNullException.ThrowIfNull(choices);
+		return GetItems(new ReadOnlySpan<T>(choices), length);
+	}
+
+	/// <inheritdoc cref="IRandom.GetItems{T}(ReadOnlySpan{T}, int)" />
+	public T[] GetItems<T>(ReadOnlySpan<T> choices, int length)
+	{
+		ArgumentOutOfRangeException.ThrowIfNegative(length);
+
+		T[] items = new T[length];
+		GetItems(choices, items.AsSpan());
+		return items;
+	}
+#endif
+
 	/// <inheritdoc cref="IRandom.Next()" />
 	public int Next()
 		=> _intGenerator?.GetNext() ?? _random.Next();
@@ -115,8 +148,6 @@ public void NextBytes(Span<byte> buffer)
 	public double NextDouble()
 		=> _doubleGenerator?.GetNext() ?? _random.NextDouble();
 
-	#endregion
-
 #if FEATURE_RANDOM_ADVANCED
 	private readonly Generator<long>? _longGenerator;
 	private readonly Generator<float>? _singleGenerator;
@@ -145,4 +176,33 @@ public long NextInt64(long minValue, long maxValue)
 	public float NextSingle()
 		=> _singleGenerator?.GetNext() ?? _random.NextSingle();
 #endif
+
+#if FEATURE_RANDOM_ITEMS
+	/// <inheritdoc cref="IRandom.Shuffle{T}(T[])" />
+	public void Shuffle<T>(T[] values)
+	{
+		ArgumentNullException.ThrowIfNull(values);
+		Shuffle(values.AsSpan());
+	}
+
+	/// <inheritdoc cref="IRandom.Shuffle{T}(Span{T})" />
+	public void Shuffle<T>(Span<T> values)
+	{
+		int n = values.Length;
+
+		for (int i = 0; i < n - 1; i++)
+		{
+			int j = Next(i, n);
+
+			if (j != i)
+			{
+				T temp = values[i];
+				values[i] = values[j];
+				values[j] = temp;
+			}
+		}
+	}
+#endif
+
+	#endregion
 }
diff --git a/Tests/Testably.Abstractions.Tests/RandomSystem/RandomTests.cs b/Tests/Testably.Abstractions.Tests/RandomSystem/RandomTests.cs
@@ -1,5 +1,8 @@
 using System.Collections.Concurrent;
 using System.Threading.Tasks;
+#if FEATURE_RANDOM_ITEMS
+using System.Linq;
+#endif
 
 namespace Testably.Abstractions.Tests.RandomSystem;
 
@@ -8,6 +11,123 @@ public abstract partial class RandomTests<TRandomSystem>
 	: RandomSystemTestBase<TRandomSystem>
 	where TRandomSystem : IRandomSystem
 {
+#if FEATURE_RANDOM_ITEMS
+	[Fact]
+	public void GetItems_Array_EmptyChoices_ShouldThrowArgumentNullException()
+	{
+		int[] choices = Array.Empty<int>();
+
+		Exception? exception = Record.Exception(() =>
+		{
+			RandomSystem.Random.Shared.GetItems(choices, 1);
+		});
+
+		exception.Should().BeException<ArgumentException>("Span may not be empty",
+			hResult: -2147024809, paramName: nameof(choices));
+	}
+
+	[Fact]
+	public void GetItems_Array_NullChoices_ShouldThrowArgumentNullException()
+	{
+		int[] choices = null!;
+
+		Exception? exception = Record.Exception(() =>
+		{
+			RandomSystem.Random.Shared.GetItems(choices, -1);
+		});
+
+		exception.Should().BeOfType<ArgumentNullException>();
+	}
+
+	[Fact]
+	public void GetItems_Array_LengthLargerThanChoices_ShouldIncludeDuplicateValues()
+	{
+		int[] choices = Enumerable.Range(0, 10).ToArray();
+
+		int[] result = RandomSystem.Random.Shared.GetItems(choices, 100);
+
+		result.Length.Should().Be(100);
+		result.Should().OnlyContain(r => choices.Contains(r));
+	}
+
+	[Theory]
+	[InlineData(-1)]
+	[InlineData(-200)]
+	public void GetItems_Array_NegativeLength_ShouldThrowArgumentOutOfRangeException(int length)
+	{
+		int[] choices = Enumerable.Range(0, 10).ToArray();
+
+		Exception? exception = Record.Exception(() =>
+		{
+			RandomSystem.Random.Shared.GetItems(choices, length);
+		});
+
+		exception.Should().BeOfType<ArgumentOutOfRangeException>()
+			.Which.Message.Should()
+			.Be(
+				$"length ('{length}') must be a non-negative value. (Parameter 'length'){Environment.NewLine}Actual value was {length}.");
+	}
+
+	[Fact]
+	public void GetItems_Array_ShouldSelectRandomElements()
+	{
+		int[] choices = Enumerable.Range(0, 100).ToArray();
+
+		int[] result = RandomSystem.Random.Shared.GetItems(choices, 10);
+
+		result.Length.Should().Be(10);
+		result.Should().OnlyContain(r => choices.Contains(r));
+	}
+
+	[Fact]
+	public void GetItems_ReadOnlySpan_LengthLargerThanChoices_ShouldIncludeDuplicateValues()
+	{
+		ReadOnlySpan<int> choices = Enumerable.Range(0, 10).ToArray().AsSpan();
+
+		int[] result = RandomSystem.Random.Shared.GetItems(choices, 100);
+
+		result.Length.Should().Be(100);
+		result.Should().OnlyContain(r => r >= 0 && r < 10);
+	}
+
+	[Fact]
+	public void GetItems_ReadOnlySpan_ShouldSelectRandomElements()
+	{
+		ReadOnlySpan<int> choices = Enumerable.Range(0, 100).ToArray().AsSpan();
+
+		int[] result = RandomSystem.Random.Shared.GetItems(choices, 10);
+
+		result.Length.Should().Be(10);
+		result.Should().OnlyContain(r => r >= 0 && r < 100);
+	}
+
+	[Fact]
+	public void GetItems_SpanDestination_LengthLargerThanChoices_ShouldIncludeDuplicateValues()
+	{
+		int[] buffer = new int[100];
+		Span<int> destination = new(buffer);
+		ReadOnlySpan<int> choices = Enumerable.Range(0, 10).ToArray().AsSpan();
+
+		RandomSystem.Random.Shared.GetItems(choices, destination);
+
+		destination.Length.Should().Be(100);
+		destination.ToArray().Should().OnlyContain(r => r >= 0 && r < 10);
+	}
+
+	[Fact]
+	public void GetItems_SpanDestination_ShouldSelectRandomElements()
+	{
+		int[] buffer = new int[10];
+		Span<int> destination = new(buffer);
+		ReadOnlySpan<int> choices = Enumerable.Range(0, 100).ToArray().AsSpan();
+
+		RandomSystem.Random.Shared.GetItems(choices, destination);
+
+		destination.Length.Should().Be(10);
+		destination.ToArray().Should().OnlyContain(r => r >= 0 && r < 100);
+	}
+#endif
+
 	[SkippableFact]
 	public void Next_MaxValue_ShouldOnlyReturnValidValues()
 	{
@@ -151,4 +271,48 @@ public void NextSingle_ShouldBeThreadSafe()
 		results.Should().OnlyHaveUniqueItems();
 	}
 #endif
+
+#if FEATURE_RANDOM_ITEMS
+	[Fact]
+	public void Shuffle_Array_ShouldShuffleItemsInPlace()
+	{
+		int[] originalValues = Enumerable.Range(0, 100).ToArray();
+		int[] values = originalValues.ToArray();
+
+		RandomSystem.Random.Shared.Shuffle(values);
+
+		values.Should().OnlyHaveUniqueItems();
+		values.Should().NotContainInOrder(originalValues);
+		values.OrderBy(x => x).Should().ContainInOrder(originalValues);
+	}
+
+	[Fact]
+	public void Shuffle_Array_Null_ShouldThrowArgumentNullException()
+	{
+		int[] values = null!;
+
+		Exception? exception = Record.Exception(() =>
+		{
+			RandomSystem.Random.Shared.Shuffle(values);
+		});
+
+		exception.Should().BeOfType<ArgumentNullException>()
+			.Which.ParamName.Should().Be(nameof(values));
+	}
+
+	[Fact]
+	public void Shuffle_Span_ShouldShuffleItemsInPlace()
+	{
+		int[] originalValues = Enumerable.Range(0, 100).ToArray();
+		int[] buffer = originalValues.ToArray();
+		Span<int> values = new(buffer);
+
+		RandomSystem.Random.Shared.Shuffle(values);
+
+		int[] result = values.ToArray();
+		result.Should().OnlyHaveUniqueItems();
+		result.Should().NotContainInOrder(originalValues);
+		result.OrderBy(x => x).Should().ContainInOrder(originalValues);
+	}
+#endif
 }