1 files changed, 118 insertions, 0 deletions
diff --git a/spec/lib/gitlab/memory/watchdog/event_reporter_spec.rb b/spec/lib/gitlab/memory/watchdog/event_reporter_spec.rb
new file mode 100644
index 00000000000..f667bc724d2
--- /dev/null
+++ b/spec/lib/gitlab/memory/watchdog/event_reporter_spec.rb
@@ -0,0 +1,118 @@
+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+require 'prometheus/client'
+
+RSpec.describe Gitlab::Memory::Watchdog::EventReporter, feature_category: :application_performance do
+  let(:logger) { instance_double(::Logger) }
+  let(:violations_counter) { instance_double(::Prometheus::Client::Counter) }
+  let(:violations_handled_counter) { instance_double(::Prometheus::Client::Counter) }
+  let(:reporter) { described_class.new(logger: logger) }
+
+  def stub_prometheus_metrics
+    allow(Gitlab::Metrics).to receive(:counter)
+                                .with(:gitlab_memwd_violations_total, anything, anything)
+                                .and_return(violations_counter)
+    allow(Gitlab::Metrics).to receive(:counter)
+                                .with(:gitlab_memwd_violations_handled_total, anything, anything)
+                                .and_return(violations_handled_counter)
+
+    allow(violations_counter).to receive(:increment)
+    allow(violations_handled_counter).to receive(:increment)
+  end
+
+  before do
+    stub_prometheus_metrics
+    allow(Gitlab::Metrics::System).to receive(:memory_usage_rss).at_least(:once).and_return(
+      total: 1024
+    )
+    allow(::Prometheus::PidProvider).to receive(:worker_id).and_return('worker_1')
+  end
+
+  describe '#logger' do
+    context 'when logger is not provided' do
+      let(:reporter) { described_class.new }
+
+      it 'uses default Gitlab::AppLogger' do
+        expect(reporter.logger).to eq(Gitlab::AppLogger)
+      end
+    end
+  end
+
+  describe '#started' do
+    it 'logs start message once' do
+      expect(logger).to receive(:info).once
+        .with(
+          pid: Process.pid,
+          worker_id: 'worker_1',
+          custom_label: 'dummy_label',
+          memwd_rss_bytes: 1024,
+          message: 'started')
+
+      reporter.started(custom_label: 'dummy_label')
+    end
+  end
+
+  describe '#stopped' do
+    subject { reporter.stopped(custom_label: 'dummy_label') }
+
+    it 'logs stop message once' do
+      expect(logger).to receive(:info).once
+        .with(
+          pid: Process.pid,
+          worker_id: 'worker_1',
+          custom_label: 'dummy_label',
+          memwd_rss_bytes: 1024,
+          message: 'stopped')
+
+      reporter.stopped(custom_label: 'dummy_label')
+    end
+  end
+
+  describe '#threshold_violated' do
+    subject { reporter.threshold_violated(:monitor_name) }
+
+    it 'increments violations counter' do
+      expect(violations_counter).to receive(:increment).with(reason: :monitor_name)
+
+      subject
+    end
+
+    it 'does not increment handled violations counter' do
+      expect(violations_handled_counter).not_to receive(:increment)
+
+      subject
+    end
+
+    it 'does not log violation' do
+      expect(logger).not_to receive(:warn)
+
+      subject
+    end
+  end
+
+  describe '#strikes_exceeded' do
+    subject { reporter.strikes_exceeded(:monitor_name, { message: 'dummy_text' }) }
+
+    before do
+      allow(logger).to receive(:warn)
+    end
+
+    it 'increments handled violations counter' do
+      expect(violations_handled_counter).to receive(:increment).with(reason: :monitor_name)
+
+      subject
+    end
+
+    it 'logs violation' do
+      expect(logger).to receive(:warn)
+        .with(
+          pid: Process.pid,
+          worker_id: 'worker_1',
+          memwd_rss_bytes: 1024,
+          message: 'dummy_text')
+
+      subject
+    end
+  end
+end