Added some Content-Type unit tests

spec/controllers/benchmark_controller_spec.rb

@@ -11,6 +11,10 @@ RSpec.describe(BenchmarkController) do
       expect(last_response).to(be_redirect)
     end
 
+    it 'Benchmark base route is an HTML response' do
+      expect(last_response['Content-Type']).to(include('text/html'))
+    end
+
     it 'Benchmark base route Location header points to /benchmark/list' do
       expect(last_response['Location']).to(eq("#{BASE_URL}/benchmark/list"))
     end
@@ -24,6 +28,10 @@ RSpec.describe(BenchmarkController) do
       expect(last_response).to(be_ok)
     end
 
+    it 'Benchmark list page is an HTML response' do
+      expect(last_response['Content-Type']).to(include('text/html'))
+    end
+
     it "Benchmark list page contains 'List of benchmarks' on page." do
       expect(last_response.body).to(include('List of benchmarks'))
     end
@@ -37,6 +45,10 @@ RSpec.describe(BenchmarkController) do
       expect(last_response).to(be_ok)
     end
 
+    it 'Benchmark add page is an HTML response' do
+      expect(last_response['Content-Type']).to(include('text/html'))
+    end
+
     it "Benchmark add page contains 'Add new benchmark' on page." do
       expect(last_response.body).to(include('Add new benchmark'))
     end