diff --git a/spec/mspec/lib/mspec/helpers/io.rb b/spec/mspec/lib/mspec/helpers/io.rb
index 57dc0d53a4..5361fb9564 100644
--- a/spec/mspec/lib/mspec/helpers/io.rb
+++ b/spec/mspec/lib/mspec/helpers/io.rb
@@ -84,6 +84,10 @@ def new_io(name, mode="w:utf-8")
   IO.new new_fd(name, options_or_mode(mode)), options_or_mode(mode)
 end
 
+def find_unused_fd
+  Dir.entries("/dev/fd").map(&:to_i).max + 1
+end
+
 # This helper simplifies passing file access modes regardless of
 # whether the :encoding feature is enabled. Only the access specifier
 # itself will be returned if :encoding is not enabled. Otherwise,
diff --git a/spec/mspec/tool/sync/sync-rubyspec.rb b/spec/mspec/tool/sync/sync-rubyspec.rb
index 120a4ad64c..e978ea17ec 100644
--- a/spec/mspec/tool/sync/sync-rubyspec.rb
+++ b/spec/mspec/tool/sync/sync-rubyspec.rb
@@ -160,9 +160,12 @@ def test_new_specs
   require "yaml"
   Dir.chdir(SOURCE_REPO) do
     versions = YAML.load_file(".travis.yml")
-    versions = versions["matrix"]["include"].map { |job| job["rvm"] }
-    versions.delete "ruby-head"
-    versions.delete "system"
+    versions = if versions.include? "matrix"
+      versions["matrix"]["include"].map { |job| job["rvm"] }
+    else
+      versions["rvm"]
+    end
+    versions = versions.grep(/^\d+\./) # Test on MRI
     min_version, max_version = versions.minmax
 
     test_command = MSPEC ? "bundle exec rspec" : "../mspec/bin/mspec -j"