Adds tests for counter increment

lib/gitlab/diff/custom_diff.rb

@@ -21,7 +21,7 @@ module Gitlab
             end
           end
         rescue Timeout::Error => e
-          rendered_timeout.increment(source: Gitlab::Runtime.sidekiq? ? BACKGROUND_EXECUTION : FOREGROUND_EXECUTION)
+          rendered_timeout.increment(source: execution_source)
           log_event(LOG_IPYNBDIFF_TIMEOUT, e)
         rescue IpynbDiff::InvalidNotebookError, IpynbDiff::InvalidTokenError => e
           log_event(LOG_IPYNBDIFF_INVALID, e)
@@ -74,6 +74,10 @@ module Gitlab
           Gitlab::Runtime.sidekiq? ? RENDERED_TIMEOUT_BACKGROUND : RENDERED_TIMEOUT_FOREGROUND
         end
 
+        def execution_source
+          Gitlab::Runtime.sidekiq? ? BACKGROUND_EXECUTION : FOREGROUND_EXECUTION
+        end
+
         def log_event(message, error = nil)
           Gitlab::AppLogger.info({ message: message })
           Gitlab::ErrorTracking.log_exception(error) if error

spec/lib/gitlab/diff/custom_diff_spec.rb

@@ -36,24 +36,45 @@ RSpec.describe Gitlab::Diff::CustomDiff do
     end
 
     context 'timeout' do
+      subject { described_class.preprocess_before_diff(ipynb_blob.path, nil, ipynb_blob) }
+
+      it 'falls back to nil on timeout' do
+        allow(Gitlab::ErrorTracking).to receive(:track_and_raise_for_dev_exception)
+        expect(Timeout).to receive(:timeout).and_raise(Timeout::Error)
+
+        expect(subject).to be_nil
+      end
+
+      context 'when in foreground' do
         it 'utilizes timeout for web' do
           expect(Timeout).to receive(:timeout).with(described_class::RENDERED_TIMEOUT_FOREGROUND).and_call_original
 
-        expect(described_class.preprocess_before_diff(ipynb_blob.path, nil, ipynb_blob)).not_to include('cells')
+          expect(subject).not_to include('cells')
         end
 
-      it 'falls back to nil on timeout' do
-        allow(Gitlab::ErrorTracking).to receive(:track_and_raise_for_dev_exception)
+        it 'increments metrics' do
           expect(Timeout).to receive(:timeout).and_raise(Timeout::Error)
+          counter = Gitlab::Metrics.counter(:rendered_timeout, 'desc')
+          expect { subject }.to change { counter.get(source: described_class::FOREGROUND_EXECUTION) }.by(1)
+        end
+      end
 
-        expect(described_class.preprocess_before_diff(ipynb_blob.path, nil, ipynb_blob)).to be_nil
+      context 'when in background' do
+        before do
+          allow(Gitlab::Runtime).to receive(:sidekiq?).and_return(true)
         end
 
         it 'utilizes longer timeout for sidekiq' do
-        allow(Gitlab::Runtime).to receive(:sidekiq?).and_return(true)
           expect(Timeout).to receive(:timeout).with(described_class::RENDERED_TIMEOUT_BACKGROUND).and_call_original
 
-        described_class.preprocess_before_diff(ipynb_blob.path, nil, ipynb_blob)
+          expect(subject).not_to include('cells')
+        end
+
+        it 'increments metrics' do
+          expect(Timeout).to receive(:timeout).and_raise(Timeout::Error)
+          counter = Gitlab::Metrics.counter(:rendered_timeout, 'desc')
+          expect { subject }.to change { counter.get(source: described_class::BACKGROUND_EXECUTION) }.by(1)
+        end
       end
     end
   end