1 files changed, 57 insertions, 0 deletions
diff --git a/spec/support/shared_examples/lib/gitlab/usage_data_counters/a_redis_counter.rb b/spec/support/shared_examples/lib/gitlab/usage_data_counters/a_redis_counter.rb
new file mode 100644
index 00000000000..91bf804978d
--- /dev/null
+++ b/spec/support/shared_examples/lib/gitlab/usage_data_counters/a_redis_counter.rb
@@ -0,0 +1,57 @@
+# frozen_string_literal: true
+
+shared_examples 'a redis usage counter' do |thing, event|
+  describe ".count(#{event})", :clean_gitlab_redis_shared_state do
+    it "increments the #{thing} #{event} counter by 1" do
+      expect do
+        described_class.count(event)
+      end.to change { described_class.read(event) }.by 1
+    end
+  end
+
+  describe ".read(#{event})", :clean_gitlab_redis_shared_state do
+    event_count = 5
+
+    it "returns the total number of #{event} events" do
+      event_count.times do
+        described_class.count(event)
+      end
+
+      expect(described_class.read(event)).to eq(event_count)
+    end
+  end
+end
+
+shared_examples 'a redis usage counter with totals' do |prefix, events|
+  describe 'totals', :clean_gitlab_redis_shared_state do
+    before do
+      events.each do |k, n|
+        n.times do
+          described_class.count(k)
+        end
+      end
+    end
+
+    let(:expected_totals) do
+      events.transform_keys { |k| "#{prefix}_#{k}".to_sym }
+    end
+
+    it 'can report all totals' do
+      expect(described_class.totals).to include(expected_totals)
+    end
+  end
+
+  # Override these let-bindings to adjust the unknown events tests
+  let(:unknown_event) { described_class::UnknownEvent }
+  let(:bad_event) { :wibble }
+
+  describe 'unknown events' do
+    it 'cannot increment' do
+      expect { described_class.count(bad_event) }.to raise_error unknown_event
+    end
+
+    it 'cannot read' do
+      expect { described_class.read(bad_event) }.to raise_error unknown_event
+    end
+  end
+end