(#18) LocalPath, AbsolutePath: migrate to the new logic for Parent calculation

Author: ForNeVeR

TruePath.Tests/AbsolutePathTests.cs

@@ -94,6 +94,18 @@ public void ReadKind_IsSymlink()
         Directory.Delete(currentDirectory, true);
     }
 
+    [Theory]
+    [InlineData("foo", ".")]
+    [InlineData("foo/bar", "foo")]
+    [InlineData("/", null)]
+    public void ParentIsCalculatedCorrectly(string relativePath, string? expectedRelativePath)
+    {
+        var root = new AbsolutePath(OperatingSystem.IsWindows() ? @"A:\" : "/");
+        var parent = root / relativePath;
+        AbsolutePath? expectedPath = expectedRelativePath == null ? null : new(root / expectedRelativePath);
+        Assert.Equal(expectedPath, parent.Parent);
+    }
+
     [Theory]
     [InlineData("/home/user", "/home/user/documents")]
     [InlineData("/home/usEr", "/home/User/documents")]

TruePath.Tests/LocalPathTests.cs

@@ -8,44 +8,41 @@ namespace TruePath.Tests;
 
 public class LocalPathTests(ITestOutputHelper output)
 {
-    [Fact]
-    public void AnyExclusivelyRelativePath()
+    [Theory]
+    [InlineData("foo", ".")]
+    [InlineData("foo/bar", "foo")]
+    [InlineData("/", null)]
+    public void AbsolutePathParent(string relativePath, string? expectedRelativePath)
     {
-        // Arrange
-        var dots = new string(Enumerable.Repeat('.', Random.Shared.Next(1, 21)).ToArray());
-        var backslashes = new string(Enumerable.Repeat(Path.DirectorySeparatorChar, Random.Shared.Next(0, 20)).ToArray());
-        var result = string.Concat(dots.AsSpan(), backslashes.AsSpan()).ToArray();
-        Random.Shared.Shuffle(result.ToArray());
-        var path = new string(result);
-
-        var localPath = new LocalPath(path);
-
-        // Act
-        var parent = localPath.Parent;
-
-        // Assert
-        Assert.Null(parent);
+        var root = new AbsolutePath(OperatingSystem.IsWindows() ? @"A:\" : "/");
+        var parent = root / relativePath;
+        AbsolutePath? expectedPath = expectedRelativePath == null ? null : new(root / expectedRelativePath);
+        Assert.Equal(expectedPath, parent.Parent);
     }
 
     [Theory]
-    [InlineData(".")]
-    [InlineData("..")]
-    [InlineData("../..")]
-    [InlineData("../../")]
-    [InlineData("../...")]
-    [InlineData(".../..")]
-    [InlineData("./.")]
-    [InlineData("../../.")]
-    public void ExclusivelyRelativePath(string path)
+    [InlineData(".", "..")]
+    [InlineData("..", "../..")]
+    [InlineData("../..", "../../..")]
+    [InlineData("../../", "../../..")]
+    [InlineData("../...", "..")]
+    [InlineData(".../..", "..")]
+    [InlineData("./.", "..")]
+    [InlineData("../../.", "../../..")]
+    [InlineData("b", ".")]
+    [InlineData("../b", "..")]
+    [InlineData("b/..", "b/../..")]
+    public void RelativePathParent(string path, string? expected)
     {
         // Arrange
         var localPath = new LocalPath(path);
+        LocalPath? expectedPath = expected == null ? null : new(expected);
 
         // Act
         var parent = localPath.Parent;
 
         // Assert
-        Assert.Null(parent);
+        Assert.Equal(expectedPath, parent);
     }
 
     [Theory]
@@ -56,8 +53,6 @@ public void ExclusivelyRelativePath(string path)
     public void IsPrefixOfShouldBeEquivalentToStartsWith(string pathA, string pathB)
     {
         // Arrange
-        var y = PathStrings.Normalize("../..");
-
         var a = new LocalPath(pathA);
         var b = new LocalPath(pathB);
 

TruePath/LocalPath.cs

@@ -16,6 +16,8 @@ namespace TruePath;
 /// </summary>
 public readonly struct LocalPath(string value) : IEquatable<LocalPath>, IPath, IPath<LocalPath>
 {
+    private static char Separator => Path.DirectorySeparatorChar;
+
     /// <inheritdoc cref="IPath.Value"/>
     public string Value { get; } = PathStrings.Normalize(value);
 
@@ -29,18 +31,14 @@ public readonly struct LocalPath(string value) : IEquatable<LocalPath>, IPath, I
     public bool IsAbsolute => Path.IsPathRooted(Value);
 
     /// <inheritdoc cref="IPath.Parent"/>
-    public LocalPath? Parent {
+    public LocalPath? Parent
+    {
         get
         {
-            var value = PathStrings.ResolveRelativePaths(Value);
-            if (string.IsNullOrWhiteSpace(value))
-            {
-                return null;
-            }
-
+            if (Value == "" || Value == ".." || Value.EndsWith($"{Separator}..")) return this / "..";
             return Path.GetDirectoryName(Value) is { } parent ? new(parent) : null;
         }
-    } 
+    }
 
     /// <inheritdoc cref="IPath.Parent"/>
     IPath? IPath.Parent => Parent;
@@ -89,7 +87,7 @@ public override int GetHashCode()
     public bool IsPrefixOf(LocalPath other)
     {
         if (!(Value.Length <= other.Value.Length && other.Value.StartsWith(Value))) return false;
-        return other.Value.Length == Value.Length || other.Value[Value.Length] == Path.DirectorySeparatorChar;
+        return other.Value.Length == Value.Length || other.Value[Value.Length] == Separator;
     }
 
     /// <summary>