diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index ed8b613..92b03e9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -40,3 +40,20 @@ jobs:
       run: bundle install
     - name: Run test
       run: rake compile test
+
+  spec:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+      - uses: ruby/setup-ruby@v1
+        with:
+          ruby-version: ruby
+      - uses: actions/checkout@v5
+        with:
+          repository: ruby/spec
+          path: rubyspec
+      - name: Clone MSpec
+        run: git clone https://github.com/ruby/mspec.git ../mspec
+      - run: bundle install
+      - run: rake compile
+      - run: ../mspec/bin/mspec -Ilib rubyspec/library/pathname
diff --git a/lib/pathname.rb b/lib/pathname.rb
index 03edc42..1c4ec6e 100644
--- a/lib/pathname.rb
+++ b/lib/pathname.rb
@@ -146,6 +146,13 @@ module ::Kernel
 # === File property and manipulation methods
 #
 # These methods are a facade for File:
+# - #each_line(*args, &block)
+# - #read(*args)
+# - #binread(*args)
+# - #readlines(*args)
+# - #sysopen(*args)
+# - #write(*args)
+# - #binwrite(*args)
 # - #atime
 # - #birthtime
 # - #ctime
@@ -184,17 +191,6 @@ module ::Kernel
 # - #mkdir(*args)
 # - #opendir(*args)
 #
-# === IO
-#
-# These methods are a facade for IO:
-# - #each_line(*args, &block)
-# - #read(*args)
-# - #binread(*args)
-# - #readlines(*args)
-# - #sysopen(*args)
-# - #write(*args)
-# - #binwrite(*args)
-#
 # === Utilities
 #
 # These methods are a mixture of Find, FileUtils, and others:
@@ -238,7 +234,11 @@ class Pathname
   # If +path+ contains a NUL character (<tt>\0</tt>), an ArgumentError is raised.
   #
   def initialize(path)
-    path = path.to_path if path.respond_to? :to_path
+    unless String === path
+      path = path.to_path if path.respond_to? :to_path
+      raise TypeError unless String === path
+    end
+
     if path.include?("\0")
       raise ArgumentError, "pathname contains \\0: #{path.inspect}"
     end
@@ -852,7 +852,7 @@ def relative_path_from(base_directory)
   end
 end
 
-class Pathname    # * IO *
+class Pathname    # * File *
   #
   # #each_line iterates over the line in the file.  It yields a String object
   # for each line.
@@ -860,34 +860,30 @@ class Pathname    # * IO *
   # This method has existed since 1.8.1.
   #
   def each_line(...) # :yield: line
-    IO.foreach(@path, ...)
+    File.foreach(@path, ...)
   end
 
-  # See <tt>IO.read</tt>.  Returns all data from the file, or the first +N+ bytes
+  # See <tt>File.read</tt>.  Returns all data from the file, or the first +N+ bytes
   # if specified.
-  def read(...) IO.read(@path, ...) end
+  def read(...) File.read(@path, ...) end
 
-  # See <tt>IO.binread</tt>.  Returns all the bytes from the file, or the first +N+
+  # See <tt>File.binread</tt>.  Returns all the bytes from the file, or the first +N+
   # if specified.
-  def binread(...) IO.binread(@path, ...) end
+  def binread(...) File.binread(@path, ...) end
 
-  # See <tt>IO.readlines</tt>.  Returns all the lines from the file.
-  def readlines(...) IO.readlines(@path, ...) end
+  # See <tt>File.readlines</tt>.  Returns all the lines from the file.
+  def readlines(...) File.readlines(@path, ...) end
 
-  # See <tt>IO.sysopen</tt>.
-  def sysopen(...) IO.sysopen(@path, ...) end
+  # See <tt>File.sysopen</tt>.
+  def sysopen(...) File.sysopen(@path, ...) end
 
   # Writes +contents+ to the file. See <tt>File.write</tt>.
-  def write(...) IO.write(@path, ...) end
+  def write(...) File.write(@path, ...) end
 
   # Writes +contents+ to the file, opening it in binary mode.
   #
   # See File.binwrite.
-  def binwrite(...) IO.binwrite(@path, ...) end
-end
-
-
-class Pathname    # * File *
+  def binwrite(...) File.binwrite(@path, ...) end
 
   # See <tt>File.atime</tt>.  Returns last access time.
   def atime() File.atime(@path) end
@@ -956,6 +952,13 @@ def truncate(length) File.truncate(@path, length) end
   # See <tt>File.utime</tt>.  Update the access and modification times.
   def utime(atime, mtime) File.utime(atime, mtime, @path) end
 
+  # Update the access and modification times of the file.
+  #
+  # Same as Pathname#utime, but does not follow symbolic links.
+  #
+  # See File.lutime.
+  def lutime(atime, mtime) File.lutime(atime, mtime, @path) end
+
   # See <tt>File.basename</tt>.  Returns the last component of the path.
   def basename(...) self.class.new(File.basename(@path, ...)) end
 
@@ -982,6 +985,13 @@ def split()
   #
   # All components of the pathname must exist when this method is called.
   def realpath(...) self.class.new(File.realpath(@path, ...)) end
+
+  # Returns the real (absolute) pathname of +self+ in the actual filesystem.
+  #
+  # Does not contain symlinks or useless dots, +..+ and +.+.
+  #
+  # The last component of the real pathname can be nonexistent.
+  def realdirpath(...) self.class.new(File.realdirpath(@path, ...)) end
 end
 
 
@@ -1219,5 +1229,5 @@ def Pathname(path) # :doc:
     return path if Pathname === path
     Pathname.new(path)
   end
-  private :Pathname
+  module_function :Pathname
 end
diff --git a/test/pathname/test_pathname.rb b/test/pathname/test_pathname.rb
index 7e0011c..e80473e 100644
--- a/test/pathname/test_pathname.rb
+++ b/test/pathname/test_pathname.rb
@@ -348,7 +348,7 @@ def has_symlink?
     rescue NotImplementedError
       return false
     rescue Errno::ENOENT
-      return false
+      return true
     rescue Errno::EACCES
       return false
     end
@@ -370,10 +370,11 @@ def has_hardlink?
   end
 
   def realpath(path, basedir=nil)
-    Pathname.new(path).realpath(basedir).to_s
+    Pathname.new(path).realpath(*basedir).to_s
   end
 
   def test_realpath
+    omit "not working yet" if RUBY_ENGINE == "jruby"
     return if !has_symlink?
     with_tmpchdir('rubytest-pathname') {|dir|
       assert_raise(Errno::ENOENT) { realpath("#{dir}/not-exist") }
@@ -434,6 +435,7 @@ def realdirpath(path)
   end
 
   def test_realdirpath
+    omit "not working yet" if RUBY_ENGINE == "jruby"
     return if !has_symlink?
     Dir.mktmpdir('rubytest-pathname') {|dir|
       rdir = realpath(dir)
@@ -1054,7 +1056,11 @@ def test_lutime
       latime = Time.utc(2000)
       lmtime = Time.utc(1999)
       File.symlink("a", "l")
-      Pathname("l").utime(latime, lmtime)
+      begin
+        Pathname("l").lutime(latime, lmtime)
+      rescue NotImplementedError
+        next
+      end
       s = File.lstat("a")
       ls = File.lstat("l")
       assert_equal(atime, s.atime)