add File.symlink

test/file.rb

@@ -115,3 +115,18 @@ assert('File.path') do
   assert_raise(TypeError) { File.path(123) }
 
 end
+
+assert('File.symlink') do
+  target_name = "/usr/bin"
+  symlink_name = "test-bin-dummy"
+  if !File.exist?(target_name)
+    skip("target directory of File.symlink is not found")
+  else
+    assert_equal 0, File.symlink(target_name, symlink_name)
+    begin
+      assert_equal true, File.symlink?(symlink_name)
+    ensure
+      File.delete symlink_name
+    end
+  end
+end