diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 035cd8a..191094d 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: [ "2.3", "2.4", "2.5", "2.6", "2.7", "3.0" ]
+        ruby-version: [ "3.0", "3.1", "3.2", "3.3", "3.4" ]
 
     steps:
       - name: Checkout
diff --git a/.gitignore b/.gitignore
index a217564..d82ea09 100644
--- a/.gitignore
+++ b/.gitignore
@@ -22,3 +22,4 @@ test/version_tmp
 *.o
 *.a
 mkmf.log
+.DS_Store
diff --git a/lib/openxml/has_attributes.rb b/lib/openxml/has_attributes.rb
index 15d3910..d97ef99 100644
--- a/lib/openxml/has_attributes.rb
+++ b/lib/openxml/has_attributes.rb
@@ -162,7 +162,7 @@ def valid_in?(value, list)
     end
 
     def matches?(value, regexp)
-      return if value =~ regexp
+      return if value.is_a?(String) && value =~ regexp
       raise ArgumentError, "Value does not match #{regexp}"
     end
 
diff --git a/test/has_properties_test.rb b/test/has_properties_test.rb
index 15a344f..78bd2d0 100644
--- a/test/has_properties_test.rb
+++ b/test/has_properties_test.rb
@@ -130,9 +130,9 @@ def tag
       end
 
       should "call to_xml on each property" do
-        builder = Nokogiri::XML::Builder.new
+        builder = OpenXml::Builder.new
         mock = MiniTest::Mock.new
-        def mock.render?; true; end
+        mock.expect(:render?, true)
         mock.expect(:to_xml, nil, [ builder ])
 
         OpenXml::Properties::BooleanProperty.stub :new, mock do
diff --git a/test/test_helper.rb b/test/test_helper.rb
index b4d9307..5958bce 100644
--- a/test/test_helper.rb
+++ b/test/test_helper.rb
@@ -9,7 +9,7 @@
 require "rr"
 
 require "minitest/reporters/turn_reporter"
-MiniTest::Reporters.use! Minitest::Reporters::TurnReporter.new
+Minitest::Reporters.use! Minitest::Reporters::TurnReporter.new
 
 require "shoulda/context"
 require "pry"