1 files changed, 88 insertions, 0 deletions
diff --git a/spec/lib/gitlab/metrics/connection_rack_middleware_spec.rb b/spec/lib/gitlab/metrics/connection_rack_middleware_spec.rb
new file mode 100644
index 00000000000..94251af305f
--- /dev/null
+++ b/spec/lib/gitlab/metrics/connection_rack_middleware_spec.rb
@@ -0,0 +1,88 @@
+require 'spec_helper'
+
+describe Gitlab::Metrics::ConnectionRackMiddleware 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 response count with status label' do
+        expect(described_class).to receive_message_chain(:rack_response_count, :increment).with(include(status: 200, method: 'get'))
+
+        subject.call(env)
+      end
+
+      it 'increments requests count' do
+        expect(described_class).to receive_message_chain(:rack_request_count, :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)
+        end
+
+        expect(described_class).to receive_message_chain(:rack_execution_time, :observe).with({}, execution_time)
+
+        subject.call(env)
+      end
+    end
+
+    context '@app.call throws exception' do
+      let(:rack_response_count) { double('rack_response_count') }
+
+      before do
+        allow(app).to receive(:call).and_raise(StandardError)
+        allow(described_class).to receive(:rack_response_count).and_return(rack_response_count)
+      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(:rack_request_count, :increment).with(method: 'get')
+
+        expect { subject.call(env) }.to raise_error(StandardError)
+      end
+
+      it "does't increment response count" do
+        expect(described_class.rack_response_count).not_to receive(:increment)
+
+        expect { subject.call(env) }.to raise_error(StandardError)
+      end
+
+      it 'measures execution time' do
+        execution_time = 10
+        allow(app).to receive(:call) do |*args|
+          Timecop.freeze(execution_time.seconds)
+          raise StandardError
+        end
+
+        expect(described_class).to receive_message_chain(:rack_execution_time, :observe).with({}, execution_time)
+
+        expect { subject.call(env) }.to raise_error(StandardError)
+      end
+    end
+  end
+end