Add test case to ensure viewBox attribute on root element of SVG

spec/svg_spec.rb

@@ -1,19 +1,21 @@
 require 'rails_helper'
 
 RSpec.describe 'SVG files' do
-  Dir[Rails.root.join('**', '*.svg')].reject { |f| f.include?('node_modules') }.each do |svg_path|
-    relative_path = svg_path.sub(Rails.root.to_s, '')
-
-    next if %w[vendor node_modules].include?(relative_path.split('/')[1])
-
+  files = Dir.glob('{app,public}/**/*.svg', base: Rails.root)
+  files.reject! { |f| f.start_with? 'public/assets/' }
+  files.each do |relative_path|
     describe relative_path do
-      it 'does not contain inline style tags (that render poorly in IE due to CSP)' do
-        doc = Nokogiri::XML(File.read(svg_path))
+      let(:subject) { Nokogiri::XML(File.read(Rails.root.join(relative_path))) }
 
-        expect(doc.css('style')).to be_empty.or(
+      it 'does not contain inline style tags (that render poorly in IE due to CSP)' do
+        expect(subject.css('style')).to be_empty.or(
           have_attributes(text: match(%r{^\s*/\*\!lint-ignore\*/})),
         )
       end
+
+      it 'defines viewBox attribute on root svg tag' do
+        expect(subject.css(':root[viewBox]')).to be_present
+      end
     end
   end
 end