Implemented Chunk and SlidingWindow on string

* Including tests
* improved naming on the old tests
* extracted common validation
* optimiziations

Funcky.Async.Test/Extensions/AsyncEnumerableExtensions/ChunkTest.cs

@@ -42,29 +42,29 @@ public async Task GivenAnEnumerableWeChanChunkItIntoAnEnumerableOfEnumerablesAsy
 
         await AsyncAssert.Collection(
             chunked,
-            a =>
+            chunk =>
             {
                 Assert.Collection(
-                    a,
-                    aa => Assert.Equal(1, aa),
-                    ab => Assert.Equal(2, ab),
-                    ac => Assert.Equal(3, ac));
+                    chunk,
+                    value => Assert.Equal(1, value),
+                    value => Assert.Equal(2, value),
+                    value => Assert.Equal(3, value));
             },
-            b =>
+            chunk =>
             {
                 Assert.Collection(
-                    b,
-                    ba => Assert.Equal(4, ba),
-                    bb => Assert.Equal(5, bb),
-                    bc => Assert.Equal(6, bc));
+                    chunk,
+                    value => Assert.Equal(4, value),
+                    value => Assert.Equal(5, value),
+                    value => Assert.Equal(6, value));
             },
-            c =>
+            chunk =>
             {
                 Assert.Collection(
-                    c,
-                    ca => Assert.Equal(7, ca),
-                    cb => Assert.Equal(8, cb),
-                    cc => Assert.Equal(9, cc));
+                    chunk,
+                    value => Assert.Equal(7, value),
+                    value => Assert.Equal(8, value),
+                    value => Assert.Equal(9, value));
             });
     }
 
@@ -79,18 +79,9 @@ public async Task GivenAnEnumerableNotAMultipleOfSizeWeHaveASmallerLastSlice()
 
         await AsyncAssert.Collection(
             chunked,
-            a =>
-            {
-                Assert.Equal(chunkSize, a.Count);
-            },
-            b =>
-            {
-                Assert.Equal(chunkSize, b.Count);
-            },
-            c =>
-            {
-                Assert.Equal(count % chunkSize, c.Count);
-            });
+            chunk => Assert.Equal(chunkSize, chunk.Count),
+            chunk => Assert.Equal(chunkSize, chunk.Count),
+            chunk => Assert.Equal(count % chunkSize, chunk.Count));
     }
 
     [Theory]

Funcky.Async.Test/Extensions/AsyncEnumerableExtensions/SlidingWindowTest.cs

@@ -41,7 +41,7 @@ public async Task GivenASourceSequenceShorterThanTheSlidingWindowWidthReturnsAnE
     }
 
     [Fact]
-    public async Task SlidingWindowReturnsTheCorrectAmountOfWindowsAllOfEvenSizeAsync()
+    public async Task SlidingWindowReturnsTheCorrectAmountOfWindowsAllOfTheSameSizeAsync()
     {
         const int width = 5;
         var source = AsyncEnumerable.Range(0, 10);
@@ -74,9 +74,9 @@ public async Task SlidingWindowReturnsASequenceOfConsecutiveWindowsAsync()
 
         await AsyncAssert.Collection(
             source.SlidingWindow(width),
-            window1 => { Assert.Equal(Enumerable.Range(0, width), window1); },
-            window2 => { Assert.Equal(Enumerable.Range(1, width), window2); },
-            window3 => { Assert.Equal(Enumerable.Range(2, width), window3); });
+            window => { Assert.Equal(Enumerable.Range(0, width), window); },
+            window => { Assert.Equal(Enumerable.Range(1, width), window); },
+            window => { Assert.Equal(Enumerable.Range(2, width), window); });
     }
 
     [Fact]

Funcky.Async/Extensions/AsyncEnumerableExtensions/Chunk.cs

@@ -1,4 +1,5 @@
 using System.Runtime.CompilerServices;
+using Funcky.Internal.Validators;
 
 namespace Funcky.Extensions;
 
@@ -13,7 +14,7 @@ public static partial class AsyncEnumerableExtensions
     /// <returns>A sequence of equally sized sequences containing elements of the source collection in the same order.</returns>
     [Pure]
     public static IAsyncEnumerable<IReadOnlyList<TSource>> Chunk<TSource>(this IAsyncEnumerable<TSource> source, int size)
-        => ChunkEnumerable(source, ValidateChunkSize(size));
+        => ChunkEnumerable(source, ChunkSizeValidator.Validate(size));
 
     /// <summary>
     /// Chunks the source sequence into equally sized chunks. The last chunk can be smaller.
@@ -26,7 +27,7 @@ public static IAsyncEnumerable<IReadOnlyList<TSource>> Chunk<TSource>(this IAsyn
     /// <returns>A sequence of results based on equally sized chunks.</returns>
     [Pure]
     public static IAsyncEnumerable<TResult> Chunk<TSource, TResult>(this IAsyncEnumerable<TSource> source, int size, Func<IReadOnlyList<TSource>, TResult> resultSelector)
-        => ChunkEnumerable(source, ValidateChunkSize(size))
+        => ChunkEnumerable(source, ChunkSizeValidator.Validate(size))
             .Select(resultSelector);
 
     /// <summary>
@@ -40,7 +41,7 @@ public static IAsyncEnumerable<TResult> Chunk<TSource, TResult>(this IAsyncEnume
     /// <returns>A sequence of results based on equally sized chunks.</returns>
     [Pure]
     public static IAsyncEnumerable<TResult> ChunkAwait<TSource, TResult>(this IAsyncEnumerable<TSource> source, int size, Func<IReadOnlyList<TSource>, ValueTask<TResult>> resultSelector)
-        => ChunkEnumerable(source, ValidateChunkSize(size))
+        => ChunkEnumerable(source, ChunkSizeValidator.Validate(size))
             .SelectAwait(resultSelector);
 
     /// <summary>
@@ -54,14 +55,9 @@ public static IAsyncEnumerable<TResult> ChunkAwait<TSource, TResult>(this IAsync
     /// <returns>A sequence of results based on equally sized chunks.</returns>
     [Pure]
     public static IAsyncEnumerable<TResult> ChunkAwaitWithCancellation<TSource, TResult>(this IAsyncEnumerable<TSource> source, int size, Func<IReadOnlyList<TSource>, CancellationToken, ValueTask<TResult>> resultSelector)
-        => ChunkEnumerable(source, ValidateChunkSize(size))
+        => ChunkEnumerable(source, ChunkSizeValidator.Validate(size))
             .SelectAwaitWithCancellation(resultSelector);
 
-    private static int ValidateChunkSize(int size)
-        => size > 0
-            ? size
-            : throw new ArgumentOutOfRangeException(nameof(size), size, "Size must be bigger than 0");
-
     private static async IAsyncEnumerable<IReadOnlyList<TSource>> ChunkEnumerable<TSource>(IAsyncEnumerable<TSource> source, int size, [EnumeratorCancellation] CancellationToken cancellationToken = default)
     {
         var asyncEnumerator = source.GetAsyncEnumerator(cancellationToken);

Funcky.Async/Extensions/AsyncEnumerableExtensions/SlidingWindow.cs

@@ -1,5 +1,6 @@
 using System.Runtime.CompilerServices;
 using Funcky.Internal;
+using Funcky.Internal.Validators;
 
 namespace Funcky.Extensions;
 
@@ -19,7 +20,7 @@ public static partial class AsyncEnumerableExtensions
     /// <returns>Returns a sequence of equally sized window sequences.</returns>
     [Pure]
     public static IAsyncEnumerable<IReadOnlyList<TSource>> SlidingWindow<TSource>(this IAsyncEnumerable<TSource> source, int width)
-        => SlidingWindowEnumerable(source, ValidateWindowWidth(width));
+        => SlidingWindowEnumerable(source, WindowWidthValidator.Validate(width));
 
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
     private static async IAsyncEnumerable<IReadOnlyList<TSource>> SlidingWindowEnumerable<TSource>(
@@ -36,10 +37,4 @@ private static async IAsyncEnumerable<IReadOnlyList<TSource>> SlidingWindowEnume
             }
         }
     }
-
-    [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    private static int ValidateWindowWidth(int width)
-        => width > 0
-            ? width
-            : throw new ArgumentOutOfRangeException(nameof(width), width, "The width of the window must be bigger than 0");
 }

Funcky.Async/Funcky.Async.csproj

@@ -14,7 +14,8 @@
         <EnableNETAnalyzers>true</EnableNETAnalyzers>
         <AnalysisModeReliability>All</AnalysisModeReliability>
         <EnablePackageValidation>true</EnablePackageValidation>
-        <NoWarn>$(NoWarn);RS0026</NoWarn><!-- RS0026: Do not add multiple overloads with optional parameters -->
+        <NoWarn>$(NoWarn);RS0026</NoWarn>
+        <!-- RS0026: Do not add multiple overloads with optional parameters -->
     </PropertyGroup>
     <PropertyGroup>
         <RootNamespace>Funcky</RootNamespace>
@@ -35,6 +36,8 @@
         <Compile Include="..\Funcky\Internal\Mixer.cs" Link="Internal\Mixer.cs" />
         <Compile Include="..\Funcky\Internal\SlidingWindowQueue.cs" Link="Internal\SlidingWindowQueue.cs" />
         <Compile Include="..\Funcky\Internal\UnsafeEither.cs" Link="Internal\UnsafeEither.cs" />
+        <Compile Include="..\Funcky\Internal\Validators\WindowWidthValidator.cs" Link="Internal\Validators\WindowWidthValidator.cs" />
+        <Compile Include="..\Funcky\Internal\Validators\ChunkSizeValidator.cs" Link="Internal\Validators\ChunkSizeValidator.cs" />
         <Compile Include="..\Funcky\Compatibility\DynamicallyAccessedMemberTypes.cs" Link="Compatibility\DynamicallyAccessedMemberTypes.cs" />
         <Compile Include="..\Funcky\Compatibility\DynamicallyAccessedMembersAttribute.cs" Link="Compatibility\DynamicallyAccessedMembersAttribute.cs" />
         <Compile Include="..\Funcky\Internal\PartitionBuilder.cs" Link="Internal\PartitionBuilder.cs" />

Funcky.Test/Extensions/EnumerableExtensions/ChunkTest.cs

@@ -31,11 +31,11 @@ public void GivenAnSingleElementListWeGetEnumerableWithOneElement()
 
         Assert.Collection(
             chunked,
-            a =>
+            chunk =>
             {
                 Assert.Collection(
-                    a,
-                    aa => Assert.Equal(1, aa));
+                    chunk,
+                    value => Assert.Equal(1, value));
             });
     }
 
@@ -48,29 +48,29 @@ public void GivenAnEnumerableWeChanChunkItIntoAnEnumerableOfEnumerables()
 
         Assert.Collection(
             chunked,
-            a =>
+            chunk =>
             {
                 Assert.Collection(
-                    a,
-                    aa => Assert.Equal(1, aa),
-                    ab => Assert.Equal(2, ab),
-                    ac => Assert.Equal(3, ac));
+                    chunk,
+                    value => Assert.Equal(1, value),
+                    value => Assert.Equal(2, value),
+                    value => Assert.Equal(3, value));
             },
-            b =>
+            chunk =>
             {
                 Assert.Collection(
-                    b,
-                    ba => Assert.Equal(4, ba),
-                    bb => Assert.Equal(5, bb),
-                    bc => Assert.Equal(6, bc));
+                    chunk,
+                    value => Assert.Equal(4, value),
+                    value => Assert.Equal(5, value),
+                    value => Assert.Equal(6, value));
             },
-            c =>
+            chunk =>
             {
                 Assert.Collection(
-                    c,
-                    ca => Assert.Equal(7, ca),
-                    cb => Assert.Equal(8, cb),
-                    cc => Assert.Equal(9, cc));
+                    chunk,
+                    value => Assert.Equal(7, value),
+                    value => Assert.Equal(8, value),
+                    value => Assert.Equal(9, value));
             });
     }
 
@@ -84,18 +84,9 @@ public void GivenAnEnumerableNotAMultipleOfSizeWeHaveASmallerLastSlice()
 
         Assert.Collection(
             chunked,
-            a =>
-            {
-                Assert.Equal(chunkSize, a.Count);
-            },
-            b =>
-            {
-                Assert.Equal(chunkSize, b.Count);
-            },
-            c =>
-            {
-                Assert.Equal(numbers.Count % chunkSize, c.Count);
-            });
+            chunk => Assert.Equal(chunkSize, chunk.Count),
+            chunk => Assert.Equal(chunkSize, chunk.Count),
+            chunk => Assert.Equal(numbers.Count % chunkSize, chunk.Count));
     }
 
     [Theory]

Funcky.Test/Extensions/EnumerableExtensions/SlidingWindowTest.cs

@@ -40,7 +40,7 @@ public void GivenASourceSequenceShorterThanTheSlidingWindowWidthReturnsAnEmptySe
     }
 
     [Fact]
-    public void SlidingWindowReturnsTheCorrectAmountOfWindowsAllOfEvenSize()
+    public void SlidingWindowReturnsTheCorrectAmountOfWindowsAllOfTheSameSize()
     {
         const int width = 5;
         var source = Enumerable.Range(0, 10);
@@ -70,8 +70,8 @@ public void SlidingWindowReturnsASequenceOfConsecutiveWindows()
 
         Assert.Collection(
             source.SlidingWindow(width),
-            window1 => { Assert.Equal(Enumerable.Range(0, width), window1); },
-            window2 => { Assert.Equal(Enumerable.Range(1, width), window2); },
-            window3 => { Assert.Equal(Enumerable.Range(2, width), window3); });
+            window => { Assert.Equal(Enumerable.Range(0, width), window); },
+            window => { Assert.Equal(Enumerable.Range(1, width), window); },
+            window => { Assert.Equal(Enumerable.Range(2, width), window); });
     }
 }

Funcky.Test/Extensions/StringExtensions/ChunkOnStringTest.cs

@@ -0,0 +1,54 @@
+using FsCheck;
+using FsCheck.Xunit;
+
+namespace Funcky.Test.Extensions.StringExtensions;
+
+public class ChunkOnStringTest
+{
+    [Property]
+    public Property ChunkingAnEmptyStringWillAlwaysYieldAndEmptySequence(PositiveInt width)
+            => string.Empty
+                .Chunk(width.Get)
+                .None()
+                .ToProperty();
+
+    [Fact]
+    public void GivenAnSingleElementListWeGetEnumerableWithOneElement()
+    {
+        var value = "a";
+
+        var chunked = value.Chunk(3);
+
+        Assert.Collection(
+            chunked,
+            chunk => Assert.Equal("a", chunk));
+    }
+
+    [Fact]
+    public void GivenAnStringWhichIsNotAMultipleOfSizeWeHaveASmallerLastString()
+    {
+        var value = "abcdefghij";
+
+        const int chunkSize = 4;
+        var chunked = value.Chunk(chunkSize);
+
+        Assert.Collection(
+            chunked,
+            chunk => Assert.Equal(chunkSize, chunk.Length),
+            chunk => Assert.Equal(chunkSize, chunk.Length),
+            chunk => Assert.Equal(value.Length % chunkSize, chunk.Length));
+    }
+
+    [Fact]
+    public void AChunkOfAStringReturnsAListOfConsecutivePartialStrings()
+    {
+        const int width = 3;
+        var source = "epsilon";
+
+        Assert.Collection(
+            source.Chunk(width),
+            chunk => { Assert.Equal("eps", chunk); },
+            chunk => { Assert.Equal("ilo", chunk); },
+            chunk => { Assert.Equal("n", chunk); });
+    }
+}

Funcky.Test/Extensions/StringExtensions/SlidingWindowOnStringTest.cs

@@ -0,0 +1,57 @@
+using FsCheck;
+using FsCheck.Xunit;
+
+namespace Funcky.Test.Extensions.StringExtensions;
+
+public class SlidingWindowOnStringTest
+{
+    [Property]
+    public Property ASlidingWindowFromAnEmptyStringWillAlwaysYieldAnEmptySequence(PositiveInt width)
+        => string.Empty
+            .SlidingWindow(width.Get)
+            .None()
+            .ToProperty();
+
+    [Fact]
+    public void SlidingWindowReturnsAListOfOverlappingPartialStrings()
+    {
+        const int width = 4;
+        var source = "epsilon";
+
+        Assert.Collection(
+            source.SlidingWindow(width),
+            window => { Assert.Equal("epsi", window); },
+            window => { Assert.Equal("psil", window); },
+            window => { Assert.Equal("silo", window); },
+            window => { Assert.Equal("ilon", window); });
+    }
+
+    [Fact]
+    public void GivenASourceStringEqualInLengthToTheSlidingWindowWidthReturnsASequenceWithOneElement()
+    {
+        var source = "gamma";
+
+        Assert.Single(source.SlidingWindow(5));
+        Assert.Equal(source, source.SlidingWindow(5).Single());
+    }
+
+    [Fact]
+    public void GivenASourceSequenceShorterThanTheSlidingWindowWidthReturnsAnEmptySequence()
+    {
+        var source = "gamma";
+
+        Assert.Empty(source.SlidingWindow(10));
+    }
+
+    [Theory]
+    [InlineData(int.MinValue)]
+    [InlineData(-42)]
+    [InlineData(-1)]
+    [InlineData(0)]
+    public void SlidingWindowThrowsOnNonPositiveWidth(int width)
+    {
+        var source = "Just a simple test!";
+
+        Assert.Throws<ArgumentOutOfRangeException>(() => source.SlidingWindow(width));
+    }
+}