Migrate ActionView::Utils tests to RSpec (#1432)

spec/ddtrace/contrib/action_view/utils_spec.rb

@@ -0,0 +1,49 @@
+RSpec.describe Datadog::Contrib::ActionView::Utils do
+  describe '#normalize_template_name' do
+    subject(:normalize_template_name) { described_class.normalize_template_name(name) }
+
+    after { Datadog.configuration[:action_view].reset! }
+
+    context 'with template path' do
+      let(:name) { '/rails/app/views/welcome/index.html.erb' }
+
+      it { is_expected.to eq('welcome/index.html.erb') }
+    end
+
+    context 'with nil template' do
+      let(:name) { nil }
+
+      it { is_expected.to be(nil) }
+    end
+
+    context 'with file name only' do
+      let(:name) { 'index.html.erb' }
+
+      it { is_expected.to eq('index.html.erb') }
+    end
+
+    context 'with template outside of `views/` directory' do
+      let(:name) { '/rails/app/other/welcome/index.html.erb' }
+
+      it { is_expected.to eq('index.html.erb') }
+    end
+
+    context 'with a custom template base path' do
+      before { Datadog.configuration[:action_view][:template_base_path] = 'custom/' }
+
+      context 'with template outside of `views/` directory' do
+        let(:name) { '/rails/app/custom/welcome/index.html.erb' }
+
+        it { is_expected.to eq('welcome/index.html.erb') }
+      end
+    end
+
+    context 'with a non-string-like argument' do
+      let(:name) { :not_a_string }
+
+      it 'stringifies arguments' do
+        is_expected.to eq('not_a_string')
+      end
+    end
+  end
+end