Allow building an absolute path from a relative one

Author: dennisdoomen

Pathy.ApiVerificationTests/ApprovedApi/pathy.net47.verified.txt

@@ -20,6 +20,8 @@ namespace Pathy
         public static Pathy.ChainablePath New { get; }
         public static Pathy.ChainablePath Temp { get; }
         public bool HasExtension(string extension) { }
+        public Pathy.ChainablePath ToAbsolute() { }
+        public object ToAbsolute(Pathy.ChainablePath parentPath) { }
         public System.IO.DirectoryInfo ToDirectoryInfo() { }
         public System.IO.FileInfo ToFileInfo() { }
         public override string ToString() { }

Pathy.ApiVerificationTests/ApprovedApi/pathy.net8.0.verified.txt

@@ -21,6 +21,8 @@ namespace Pathy
         public static Pathy.ChainablePath Temp { get; }
         public Pathy.ChainablePath AsRelativeTo(Pathy.ChainablePath basePath) { }
         public bool HasExtension(string extension) { }
+        public Pathy.ChainablePath ToAbsolute() { }
+        public object ToAbsolute(Pathy.ChainablePath parentPath) { }
         public System.IO.DirectoryInfo ToDirectoryInfo() { }
         public System.IO.FileInfo ToFileInfo() { }
         public override string ToString() { }

Pathy.ApiVerificationTests/ApprovedApi/pathy.netstandard2.0.verified.txt

@@ -20,6 +20,8 @@ namespace Pathy
         public static Pathy.ChainablePath New { get; }
         public static Pathy.ChainablePath Temp { get; }
         public bool HasExtension(string extension) { }
+        public Pathy.ChainablePath ToAbsolute() { }
+        public object ToAbsolute(Pathy.ChainablePath parentPath) { }
         public System.IO.DirectoryInfo ToDirectoryInfo() { }
         public System.IO.FileInfo ToFileInfo() { }
         public override string ToString() { }

Pathy.ApiVerificationTests/ApprovedApi/pathy.netstandard2.1.verified.txt

@@ -21,6 +21,8 @@ namespace Pathy
         public static Pathy.ChainablePath Temp { get; }
         public Pathy.ChainablePath AsRelativeTo(Pathy.ChainablePath basePath) { }
         public bool HasExtension(string extension) { }
+        public Pathy.ChainablePath ToAbsolute() { }
+        public object ToAbsolute(Pathy.ChainablePath parentPath) { }
         public System.IO.DirectoryInfo ToDirectoryInfo() { }
         public System.IO.FileInfo ToFileInfo() { }
         public override string ToString() { }

Pathy.Specs/ChainablePathSpecs.cs

@@ -116,6 +116,47 @@ public void Can_build_from_a_relative_path()
         path.IsRooted.Should().BeFalse();
     }
 
+    [Fact]
+    public void Can_convert_the_relative_path_to_an_absolute_path_using_the_current_working_directory()
+    {
+        // Arrange
+        var path = ChainablePath.From("temp/somefile.txt");
+
+        // Act
+        var absolutePath = path.ToAbsolute();
+
+        // Assert
+        absolutePath.ToString().Should().Be(Path.Combine(Environment.CurrentDirectory, "temp", "somefile.txt"));
+    }
+
+    [Fact]
+    public void Can_combine_a_relative_path_using_a_specific_absolute_path()
+    {
+        // Arrange
+        var path = ChainablePath.From("temp/somefile.txt");
+
+        // Act
+        var absolutePath = path.ToAbsolute(ChainablePath.Temp);
+
+        // Assert
+        absolutePath.ToString().Should().Be(Path.Combine(Path.GetTempPath(), "temp", "somefile.txt"));
+    }
+
+    [Theory]
+    [InlineData("")]
+    [InlineData(null)]
+    public void The_absolute_path_must_be_valid(string absolutePath)
+    {
+        // Arrange
+        var path = ChainablePath.From("temp/somefile.txt");
+
+        // Act
+        Action act = () => path.ToAbsolute(absolutePath);
+
+        // Assert
+        act.Should().Throw<ArgumentException>("*absolutePath*");
+    }
+
     [Fact]
     public void Can_start_with_an_empty_path()
     {

Pathy/ChainablePath.cs

@@ -341,6 +341,28 @@ public bool HasExtension(string extension)
 
         return string.Equals(Extension, extension, StringComparison.OrdinalIgnoreCase);
     }
+
+    /// <summary>
+    /// Converts the current <see cref="ChainablePath"/> to an absolute path using the current working directory.
+    /// </summary>
+    public ChainablePath ToAbsolute()
+    {
+        return Path.GetFullPath(this);
+    }
+
+    /// <summary>
+    /// Converts the current <see cref="ChainablePath"/> instance to an absolute path, using the specified parent
+    /// path as the base.
+    /// </summary>
+    public object ToAbsolute(ChainablePath parentPath)
+    {
+        if (!parentPath.IsRooted)
+        {
+            throw new ArgumentException("Parent path must be an absolute path", nameof(parentPath));
+        }
+
+        return From(Path.Combine(parentPath.ToString(), this.ToString()));
+    }
 }
 
 #if PATHY_PUBLIC

README.md

@@ -114,6 +114,9 @@ Given an instance of `ChainablePath`, you can get a lot of useful information:
 * Want to know the delta between two paths? Use `AsRelativeTo`.
 * To determine if a file has a case-insensitive extension, use `HasExtension(".txt")` or `HasExtension("txt")`.
 
+Other features
+* Build an absolute path from a relative path using `ToAbsolute` to use the current directory as the base or `ToAbsolute(parentPath)` to use something else as the base.
+
 And if the built-in functionality really isn't enough, you can always call `ToDirectoryInfo` or `ToFileInfo` to continue with an instance of `DirectoryInfo` and `FileInfo`.
 
 ### Globbing