prefer assert_select over a regex parsing the rendered page

Author: anarchivist

spec/views/preview/preview/index.html.erb_spec.rb

@@ -8,6 +8,6 @@
 
     render
 
-    expect(rendered).to match(/#{endpoint}/)
+    assert_select "div#galc-app:match('data-api-base-url', ?)", endpoint
   end
 end