Added some Content-Type unit tests

spec/controllers/reports_controller_spec.rb

@@ -10,7 +10,11 @@ RSpec.describe(ReportsController) do
       expect(last_response).to(be_ok)
     end
 
-    it "Reports page contains 'Generate report' on page." do
+    it 'Reports page is an HTML response' do
+      expect(last_response['Content-Type']).to(include('text/html'))
+    end
+
+    it 'Reports page contains "Generate report" on page.' do
       expect(last_response.body).to(include('Generate report'))
     end
   end