1 files changed, 71 insertions, 0 deletions
diff --git a/spec/lib/gitlab/metrics/requests_rack_middleware_spec.rb b/spec/lib/gitlab/metrics/requests_rack_middleware_spec.rb
new file mode 100644
index 00000000000..461b1e4182a
--- /dev/null
+++ b/spec/lib/gitlab/metrics/requests_rack_middleware_spec.rb
@@ -0,0 +1,71 @@
+require 'spec_helper'
+
+describe Gitlab::Metrics::RequestsRackMiddleware do
+  let(:app) { double('app') }
+  subject { described_class.new(app) }
+
+  around do |example|
+    Timecop.freeze { example.run }
+  end
+
+  describe '#call' do
+    let(:status) { 100 }
+    let(:env) { { 'REQUEST_METHOD' => 'GET' } }
+    let(:stack_result) { [status, {}, 'body'] }
+
+    before do
+      allow(app).to receive(:call).and_return(stack_result)
+    end
+
+    context '@app.call succeeds with 200' do
+      before do
+        allow(app).to receive(:call).and_return([200, nil, nil])
+      end
+
+      it 'increments requests count' do
+        expect(described_class).to receive_message_chain(:http_request_total, :increment).with(method: 'get')
+
+        subject.call(env)
+      end
+
+      it 'measures execution time' do
+        execution_time = 10
+        allow(app).to receive(:call) do |*args|
+          Timecop.freeze(execution_time.seconds)
+          [200, nil, nil]
+        end
+
+        expect(described_class).to receive_message_chain(:http_request_duration_seconds, :observe).with({ status: 200, method: 'get' }, execution_time)
+
+        subject.call(env)
+      end
+    end
+
+    context '@app.call throws exception' do
+      let(:http_request_duration_seconds) { double('http_request_duration_seconds') }
+
+      before do
+        allow(app).to receive(:call).and_raise(StandardError)
+        allow(described_class).to receive(:http_request_duration_seconds).and_return(http_request_duration_seconds)
+      end
+
+      it 'increments exceptions count' do
+        expect(described_class).to receive_message_chain(:rack_uncaught_errors_count, :increment)
+
+        expect { subject.call(env) }.to raise_error(StandardError)
+      end
+
+      it 'increments requests count' do
+        expect(described_class).to receive_message_chain(:http_request_total, :increment).with(method: 'get')
+
+        expect { subject.call(env) }.to raise_error(StandardError)
+      end
+
+      it "does't measure request execution time" do
+        expect(described_class.http_request_duration_seconds).not_to receive(:increment)
+
+        expect { subject.call(env) }.to raise_error(StandardError)
+      end
+    end
+  end
+end