fix: directory with forward slash exists on windows

Author: vbreuss

Source/Testably.Abstractions.Testing/Helpers/Execute.WindowsPath.cs

@@ -32,7 +32,11 @@ public override string GetFullPath(string path)
 			string candidate;
 			if (!string.IsNullOrEmpty(pathRoot) && !string.IsNullOrEmpty(directoryRoot))
 			{
-				if (char.ToUpperInvariant(pathRoot[0]) != char.ToUpperInvariant(directoryRoot[0]))
+				if (pathRoot[0] == DirectorySeparatorChar)
+				{
+					candidate = directoryRoot;
+				}
+				else if (char.ToUpperInvariant(pathRoot[0]) != char.ToUpperInvariant(directoryRoot[0]))
 				{
 					candidate = path;
 				}

Tests/Testably.Abstractions.Tests/FileSystem/Directory/ExistsTests.cs

@@ -26,6 +26,14 @@ public void Exists_File_ShouldReturnFalse(string path)
 		result.Should().BeFalse();
 	}
 
+	[Fact]
+	public void Exists_ForwardSlash_ShouldReturnTrue()
+	{
+		bool result = FileSystem.Directory.Exists("/");
+
+		result.Should().BeTrue();
+	}
+
 	[Theory]
 	[InlineData(@"\\s")]
 	[InlineData("<")]

Tests/Testably.Abstractions.Tests/FileSystem/DirectoryInfo/ExistsTests.cs

@@ -36,6 +36,14 @@ public void Exists_File_ShouldReturnFalse(string path)
 		sut.Exists.Should().BeFalse();
 	}
 
+	[Fact]
+	public void Exists_ForwardSlash_ShouldReturnTrue()
+	{
+		IDirectoryInfo sut = FileSystem.DirectoryInfo.New("/");
+
+		sut.Exists.Should().BeTrue();
+	}
+
 	[Theory]
 	[AutoData]
 	public void Exists_NotExistedPreviously_ShouldOnlyUpdateOnInitialization(string path)