fix: implementation of Path.GetRelativePath (#336)

Prototype implementation for TestableIO/System.IO.Abstractions#773, similar to [the implementation in .NET Runtime](https://github.com/dotnet/runtime/blob/release/7.0/src/libraries/System.Private.CoreLib/src/System/IO/Path.cs#L886) --------- Co-authored-by: Valentin Breuß <v.breuss@tig.at>
Testably · Jul 24, 2023 · a7e455a · a7e455a
1 parent 3cabe7d
commit a7e455a
Show file tree

Hide file tree

Showing 3 changed files with 29 additions and 7 deletions.
diff --git a/Source/Testably.Abstractions.Interface/Helpers/PathSystemBase.cs b/Source/Testably.Abstractions.Interface/Helpers/PathSystemBase.cs
@@ -146,7 +146,7 @@ public string GetRandomFileName()
 
 #if FEATURE_PATH_RELATIVE
 	/// <inheritdoc cref="Path.GetRelativePath(string, string)" />
-	public string GetRelativePath(string relativeTo, string path)
+	public virtual string GetRelativePath(string relativeTo, string path)
 		=> Path.GetRelativePath(relativeTo, path);
 #endif
 

diff --git a/Source/Testably.Abstractions.Testing/FileSystem/PathMock.cs b/Source/Testably.Abstractions.Testing/FileSystem/PathMock.cs
@@ -41,4 +41,18 @@ public override string GetFullPath(string path)
 			_fileSystem.Storage.CurrentDirectory,
 			path));
 	}
+
+#if FEATURE_PATH_RELATIVE
+	/// <inheritdoc cref="IPath.GetRelativePath(string, string)" />
+	public override string GetRelativePath(string relativeTo, string path)
+	{
+		relativeTo.EnsureValidArgument(FileSystem, nameof(relativeTo));
+		path.EnsureValidArgument(FileSystem, nameof(path));
+
+		relativeTo = FileSystem.Path.GetFullPath(relativeTo);
+		path = FileSystem.Path.GetFullPath(path);
+
+		return Path.GetRelativePath(relativeTo, path);
+	}
+#endif
 }
diff --git a/Tests/Testably.Abstractions.Tests/FileSystem/Path/GetRelativePathTests.cs b/Tests/Testably.Abstractions.Tests/FileSystem/Path/GetRelativePathTests.cs
@@ -25,11 +25,7 @@ public void GetRelativePath_CommonParentDirectory_ShouldReturnRelativePath(
 	public void GetRelativePath_DifferentDrives_ShouldReturnAbsolutePath(
 		string path1, string path2)
 	{
-		if (!Test.RunsOnWindows)
-		{
-			// Different drives are only supported on Windows
-			return;
-		}
+		Skip.IfNot(Test.RunsOnWindows, "Different drives are only supported on Windows");
 
 		path1 = FileTestHelper.RootDrive(path1, 'A');
 		path2 = FileTestHelper.RootDrive(path2, 'B');
@@ -38,6 +34,18 @@ public void GetRelativePath_DifferentDrives_ShouldReturnAbsolutePath(
 		result.Should().Be(path2);
 	}
 
+	[Fact]
+	public void GetRelativePath_FromAbsolutePathInCurrentDirectory_ShouldReturnRelativePath()
+	{
+		string rootedPath = FileSystem.Path.Combine(BasePath, "input");
+		FileSystem.Directory.CreateDirectory(rootedPath);
+		FileSystem.Directory.SetCurrentDirectory(rootedPath);
+
+		string result = FileSystem.Path.GetRelativePath(rootedPath, "a.txt");
+
+		Assert.Equal("a.txt", result);
+	}
+
 	[SkippableTheory]
 	[AutoData]
 	public void GetRelativePath_RootedPath_ShouldReturnAbsolutePath(
@@ -56,7 +64,7 @@ public void GetRelativePath_RootedPath_ShouldReturnAbsolutePath(
 	public void GetRelativePath_RootedPath_ShouldWorkOnAnyDrive()
 	{
 		Skip.IfNot(Test.RunsOnWindows);
-		
+
 		string rootedPath = "/dir/subDirectory";
 		FileSystem.Directory.CreateDirectory(rootedPath);
 		string directory = FileSystem.Directory.GetDirectories("/dir").Single();