diff --git a/spec/docker_image/image_spec.rb b/spec/docker_image/image_spec.rb
index c2a23a9..59272c6 100644
--- a/spec/docker_image/image_spec.rb
+++ b/spec/docker_image/image_spec.rb
@@ -78,7 +78,7 @@ describe 'Dockerfile' do
     end
 
     it 'does not expose php version' do
-      expect(file(php_conf).content).to match '^php_flag\[expose_php\]\s+=\s+off$'
+      expect(file(php_conf).content).to match(/^php_flag\[expose_php\]\s+=\s+off$/)
     end
   end