1 files changed, 77 insertions, 0 deletions
diff --git a/spec/lib/gitlab/correlation_id_spec.rb b/spec/lib/gitlab/correlation_id_spec.rb
new file mode 100644
index 00000000000..584d1f48386
--- /dev/null
+++ b/spec/lib/gitlab/correlation_id_spec.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+
+describe Gitlab::CorrelationId do
+  describe '.use_id' do
+    it 'yields when executed' do
+      expect { |blk| described_class.use_id('id', &blk) }.to yield_control
+    end
+
+    it 'stacks correlation ids' do
+      described_class.use_id('id1') do
+        described_class.use_id('id2') do |current_id|
+          expect(current_id).to eq('id2')
+        end
+      end
+    end
+
+    it 'for missing correlation id it generates random one' do
+      described_class.use_id('id1') do
+        described_class.use_id(nil) do |current_id|
+          expect(current_id).not_to be_empty
+          expect(current_id).not_to eq('id1')
+        end
+      end
+    end
+  end
+
+  describe '.current_id' do
+    subject { described_class.current_id }
+
+    it 'returns last correlation id' do
+      described_class.use_id('id1') do
+        described_class.use_id('id2') do
+          is_expected.to eq('id2')
+        end
+      end
+    end
+  end
+
+  describe '.current_or_new_id' do
+    subject { described_class.current_or_new_id }
+
+    context 'when correlation id is set' do
+      it 'returns last correlation id' do
+        described_class.use_id('id1') do
+          is_expected.to eq('id1')
+        end
+      end
+    end
+
+    context 'when correlation id is missing' do
+      it 'returns a new correlation id' do
+        expect(described_class).to receive(:new_id)
+          .and_call_original
+
+        is_expected.not_to be_empty
+      end
+    end
+  end
+
+  describe '.ids' do
+    subject { described_class.send(:ids) }
+
+    it 'returns empty list if not correlation is used' do
+      is_expected.to be_empty
+    end
+
+    it 'returns list if correlation ids are used' do
+      described_class.use_id('id1') do
+        described_class.use_id('id2') do
+          is_expected.to eq(%w(id1 id2))
+        end
+      end
+    end
+  end
+end