From 95cd3e8cbcd0e0eb982acdee8536f19b4fa0a3e3 Mon Sep 17 00:00:00 2001
From: Oliver Booth <me@olivr.me>
Date: Sun, 2 Apr 2023 00:36:31 +0100
Subject: [PATCH] test: bring coverage to 100% for
 X10D.Collections.SpanExtensions

---
 X10D.Tests/src/Collections/SpanTest.cs | 391 ++++++++++++++++++++++++-
 1 file changed, 378 insertions(+), 13 deletions(-)

diff --git a/X10D.Tests/src/Collections/SpanTest.cs b/X10D.Tests/src/Collections/SpanTest.cs
index 106bf80..7506ca9 100644
--- a/X10D.Tests/src/Collections/SpanTest.cs
+++ b/X10D.Tests/src/Collections/SpanTest.cs
@@ -16,6 +16,16 @@ public class SpanTest
         Assert.AreEqual(0, count);
     }
 
+    [TestMethod]
+    public void Count_ShouldReturn0_GivenEmptyReadOnlySpan()
+    {
+        ReadOnlySpan<int> span = ReadOnlySpan<int>.Empty;
+
+        int count = span.Count(2);
+
+        Assert.AreEqual(0, count);
+    }
+
     [TestMethod]
     public void Count_ShouldReturn8_GivenSpanWith8MatchingElements()
     {
@@ -27,7 +37,17 @@ public class SpanTest
     }
 
     [TestMethod]
-    public void Split_OnEmptySpan_ShouldYieldNothing()
+    public void Count_ShouldReturn8_GivenReadOnlySpanWith8MatchingElements()
+    {
+        ReadOnlySpan<int> span = stackalloc int[16] {1, 2, 3, 2, 5, 2, 7, 2, 9, 2, 11, 2, 13, 2, 15, 2};
+
+        int count = span.Count(2);
+
+        Assert.AreEqual(8, count);
+    }
+
+    [TestMethod]
+    public void Split_OnEmptySpan_ShouldYieldNothing_UsingCharDelimiter_GivenReadOnlySpan()
     {
         ReadOnlySpan<char> span = ReadOnlySpan<char>.Empty;
 
@@ -41,7 +61,49 @@ public class SpanTest
     }
 
     [TestMethod]
-    public void Split_OnOneWord_ShouldYieldLength1()
+    public void Split_OnEmptySpan_ShouldYieldNothing_UsingCharDelimiter_GivenSpan()
+    {
+        Span<char> span = Span<char>.Empty;
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> unused in span.Split(' '))
+        {
+            index++;
+        }
+
+        Assert.AreEqual(0, index);
+    }
+
+    [TestMethod]
+    public void Split_OnEmptySpan_ShouldYieldNothing_UsingStringDelimiter_GivenReadOnlySpan()
+    {
+        ReadOnlySpan<char> span = ReadOnlySpan<char>.Empty;
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> unused in span.Split(" "))
+        {
+            index++;
+        }
+
+        Assert.AreEqual(0, index);
+    }
+
+    [TestMethod]
+    public void Split_OnEmptySpan_ShouldYieldNothing_UsingStringDelimiter_GivenSpan()
+    {
+        Span<char> span = Span<char>.Empty;
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> unused in span.Split(" "))
+        {
+            index++;
+        }
+
+        Assert.AreEqual(0, index);
+    }
+
+    [TestMethod]
+    public void Split_OnOneWord_ShouldYieldLength1_UsingCharDelimiter_GivenReadOnlySpan()
     {
         ReadOnlySpan<char> span = "Hello ".AsSpan();
 
@@ -60,9 +122,11 @@ public class SpanTest
     }
 
     [TestMethod]
-    public void Split_OnTwoWords_ShouldYieldLength2()
+    public void Split_OnOneWord_ShouldYieldLength1_UsingCharDelimiter_GivenSpan()
     {
-        ReadOnlySpan<char> span = "Hello World ".AsSpan();
+        ReadOnlySpan<char> source = "Hello ".AsSpan();
+        Span<char> span = stackalloc char[source.Length];
+        source.CopyTo(span);
 
         var index = 0;
         foreach (ReadOnlySpan<char> subSpan in span.Split(' '))
@@ -71,9 +135,149 @@ public class SpanTest
             {
                 Assert.AreEqual("Hello", subSpan.ToString());
             }
-            else if (index == 1)
+
+            index++;
+        }
+
+        Assert.AreEqual(1, index);
+    }
+
+    [TestMethod]
+    public void Split_OnOneWord_ShouldYieldLength1_UsingStringDelimiter_GivenReadOnlySpan()
+    {
+        ReadOnlySpan<char> span = "Hello ".AsSpan();
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(" "))
+        {
+            if (index == 0)
             {
-                Assert.AreEqual("World", subSpan.ToString());
+                Assert.AreEqual("Hello", subSpan.ToString());
+            }
+
+            index++;
+        }
+
+        Assert.AreEqual(1, index);
+    }
+
+    [TestMethod]
+    public void Split_OnOneWord_ShouldYieldLength1_UsingStringDelimiter_GivenSpan()
+    {
+        ReadOnlySpan<char> source = "Hello ".AsSpan();
+        Span<char> span = stackalloc char[source.Length];
+        source.CopyTo(span);
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(" "))
+        {
+            if (index == 0)
+            {
+                Assert.AreEqual("Hello", subSpan.ToString());
+            }
+
+            index++;
+        }
+
+        Assert.AreEqual(1, index);
+    }
+
+    [TestMethod]
+    public void Split_OnOneWordWithoutDelimiter_ShouldYieldLength1_UsingCharDelimiter_GivenReadOnlySpan()
+    {
+        ReadOnlySpan<char> span = "Hello".AsSpan();
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(' '))
+        {
+            if (index == 0)
+            {
+                Assert.AreEqual("Hello", subSpan.ToString());
+            }
+
+            index++;
+        }
+
+        Assert.AreEqual(1, index);
+    }
+
+    [TestMethod]
+    public void Split_OnOneWordWithoutDelimiter_ShouldYieldLength1_UsingCharDelimiter_GivenSpan()
+    {
+        ReadOnlySpan<char> source = "Hello".AsSpan();
+        Span<char> span = stackalloc char[source.Length];
+        source.CopyTo(span);
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(' '))
+        {
+            if (index == 0)
+            {
+                Assert.AreEqual("Hello", subSpan.ToString());
+            }
+
+            index++;
+        }
+
+        Assert.AreEqual(1, index);
+    }
+
+    [TestMethod]
+    public void Split_OnOneWordWithoutDelimiter_ShouldYieldLength1_UsingStringDelimiter_GivenReadOnlySpan()
+    {
+        ReadOnlySpan<char> span = "Hello".AsSpan();
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(" "))
+        {
+            if (index == 0)
+            {
+                Assert.AreEqual("Hello", subSpan.ToString());
+            }
+
+            index++;
+        }
+
+        Assert.AreEqual(1, index);
+    }
+
+    [TestMethod]
+    public void Split_OnOneWordWithoutDelimiter_ShouldYieldLength1_UsingStringDelimiter_GivenSpan()
+    {
+        ReadOnlySpan<char> source = "Hello".AsSpan();
+        Span<char> span = stackalloc char[source.Length];
+        source.CopyTo(span);
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(" "))
+        {
+            if (index == 0)
+            {
+                Assert.AreEqual("Hello", subSpan.ToString());
+            }
+
+            index++;
+        }
+
+        Assert.AreEqual(1, index);
+    }
+
+    [TestMethod]
+    public void Split_OnTwoWords_ShouldYieldLength2_UsingCharDelimiter_GivenReadOnlySpan()
+    {
+        ReadOnlySpan<char> span = "Hello World ".AsSpan();
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(' '))
+        {
+            switch (index)
+            {
+                case 0:
+                    Assert.AreEqual("Hello", subSpan.ToString());
+                    break;
+                case 1:
+                    Assert.AreEqual("World", subSpan.ToString());
+                    break;
             }
 
             index++;
@@ -83,24 +287,185 @@ public class SpanTest
     }
 
     [TestMethod]
-    public void Split_OnThreeWords_ShouldYieldLength3()
+    public void Split_OnTwoWords_ShouldYieldLength2_UsingCharDelimiter_GivenSpan()
+    {
+        ReadOnlySpan<char> source = "Hello World ".AsSpan();
+        Span<char> span = stackalloc char[source.Length];
+        source.CopyTo(span);
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(' '))
+        {
+            switch (index)
+            {
+                case 0:
+                    Assert.AreEqual("Hello", subSpan.ToString());
+                    break;
+                case 1:
+                    Assert.AreEqual("World", subSpan.ToString());
+                    break;
+            }
+
+            index++;
+        }
+
+        Assert.AreEqual(2, index);
+    }
+
+    [TestMethod]
+    public void Split_OnTwoWords_ShouldYieldLength2_UsingStringDelimiter_GivenReadOnlySpan()
+    {
+        ReadOnlySpan<char> span = "Hello World ".AsSpan();
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(" "))
+        {
+            switch (index)
+            {
+                case 0:
+                    Assert.AreEqual("Hello", subSpan.ToString());
+                    break;
+                case 1:
+                    Assert.AreEqual("World", subSpan.ToString());
+                    break;
+            }
+
+            index++;
+        }
+
+        Assert.AreEqual(2, index);
+    }
+
+    [TestMethod]
+    public void Split_OnTwoWords_ShouldYieldLength2_UsingStringDelimiter_GivenSpan()
+    {
+        ReadOnlySpan<char> source = "Hello World ".AsSpan();
+        Span<char> span = stackalloc char[source.Length];
+        source.CopyTo(span);
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(" "))
+        {
+            switch (index)
+            {
+                case 0:
+                    Assert.AreEqual("Hello", subSpan.ToString());
+                    break;
+                case 1:
+                    Assert.AreEqual("World", subSpan.ToString());
+                    break;
+            }
+
+            index++;
+        }
+
+        Assert.AreEqual(2, index);
+    }
+
+    [TestMethod]
+    public void Split_OnThreeWords_ShouldYieldLength3_UsingCharDelimiter_GivenReadOnlySpan()
     {
         ReadOnlySpan<char> span = "Hello, the World ".AsSpan();
 
         var index = 0;
         foreach (ReadOnlySpan<char> subSpan in span.Split(' '))
         {
-            if (index == 0)
+            switch (index)
             {
-                Assert.AreEqual("Hello,", subSpan.ToString());
+                case 0:
+                    Assert.AreEqual("Hello,", subSpan.ToString());
+                    break;
+                case 1:
+                    Assert.AreEqual("the", subSpan.ToString());
+                    break;
+                case 2:
+                    Assert.AreEqual("World", subSpan.ToString());
+                    break;
             }
-            else if (index == 1)
+
+            index++;
+        }
+
+        Assert.AreEqual(3, index);
+    }
+
+    [TestMethod]
+    public void Split_OnThreeWords_ShouldYieldLength3_UsingCharDelimiter_GivenSpan()
+    {
+        ReadOnlySpan<char> source = "Hello, the World ".AsSpan();
+        Span<char> span = stackalloc char[source.Length];
+        source.CopyTo(span);
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(' '))
+        {
+            switch (index)
             {
-                Assert.AreEqual("the", subSpan.ToString());
+                case 0:
+                    Assert.AreEqual("Hello,", subSpan.ToString());
+                    break;
+                case 1:
+                    Assert.AreEqual("the", subSpan.ToString());
+                    break;
+                case 2:
+                    Assert.AreEqual("World", subSpan.ToString());
+                    break;
             }
-            else if (index == 2)
+
+            index++;
+        }
+
+        Assert.AreEqual(3, index);
+    }
+
+    [TestMethod]
+    public void Split_OnThreeWords_ShouldYieldLength3_UsingStringDelimiter_GivenReadOnlySpan()
+    {
+        ReadOnlySpan<char> span = "Hello, the World ".AsSpan();
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(" "))
+        {
+            switch (index)
             {
-                Assert.AreEqual("World", subSpan.ToString());
+                case 0:
+                    Assert.AreEqual("Hello,", subSpan.ToString());
+                    break;
+                case 1:
+                    Assert.AreEqual("the", subSpan.ToString());
+                    break;
+                case 2:
+                    Assert.AreEqual("World", subSpan.ToString());
+                    break;
+            }
+
+            index++;
+        }
+
+        Assert.AreEqual(3, index);
+    }
+
+    [TestMethod]
+    public void Split_OnThreeWords_ShouldYieldLength3_UsingStringDelimiter_GivenSpan()
+    {
+        ReadOnlySpan<char> source = "Hello, the World ".AsSpan();
+        Span<char> span = stackalloc char[source.Length];
+        source.CopyTo(span);
+
+        var index = 0;
+        foreach (ReadOnlySpan<char> subSpan in span.Split(" "))
+        {
+            switch (index)
+            {
+                case 0:
+                    Assert.AreEqual("Hello,", subSpan.ToString());
+                    break;
+                case 1:
+                    Assert.AreEqual("the", subSpan.ToString());
+                    break;
+                case 2:
+                    Assert.AreEqual("World", subSpan.ToString());
+                    break;
             }
 
             index++;