1 files changed, 163 insertions, 0 deletions
diff --git a/spec/lib/gitlab/etag_caching/middleware_spec.rb b/spec/lib/gitlab/etag_caching/middleware_spec.rb
new file mode 100644
index 00000000000..8b5bfc4dbb0
--- /dev/null
+++ b/spec/lib/gitlab/etag_caching/middleware_spec.rb
@@ -0,0 +1,163 @@
+require 'spec_helper'
+
+describe Gitlab::EtagCaching::Middleware do
+  let(:app) { double(:app) }
+  let(:middleware) { described_class.new(app) }
+  let(:app_status_code) { 200 }
+  let(:if_none_match) { nil }
+  let(:enabled_path) { '/gitlab-org/gitlab-ce/noteable/issue/1/notes' }
+
+  context 'when ETag caching is not enabled for current route' do
+    let(:path) { '/gitlab-org/gitlab-ce/tree/master/noteable/issue/1/notes' }
+
+    before do
+      mock_app_response
+    end
+
+    it 'does not add ETag header' do
+      _, headers, _ = middleware.call(build_env(path, if_none_match))
+
+      expect(headers['ETag']).to be_nil
+    end
+
+    it 'passes status code from app' do
+      status, _, _ = middleware.call(build_env(path, if_none_match))
+
+      expect(status).to eq app_status_code
+    end
+  end
+
+  context 'when there is no ETag in store for given resource' do
+    let(:path) { enabled_path }
+
+    before do
+      mock_app_response
+      mock_value_in_store(nil)
+    end
+
+    it 'generates ETag' do
+      expect_any_instance_of(Gitlab::EtagCaching::Store)
+        .to receive(:touch).and_return('123')
+
+      middleware.call(build_env(path, if_none_match))
+    end
+
+    context 'when If-None-Match header was specified' do
+      let(:if_none_match) { 'W/"abc"' }
+
+      it 'tracks "etag_caching_key_not_found" event' do
+        expect(Gitlab::Metrics).to receive(:add_event)
+          .with(:etag_caching_middleware_used)
+        expect(Gitlab::Metrics).to receive(:add_event)
+          .with(:etag_caching_key_not_found)
+
+        middleware.call(build_env(path, if_none_match))
+      end
+    end
+  end
+
+  context 'when there is ETag in store for given resource' do
+    let(:path) { enabled_path }
+
+    before do
+      mock_app_response
+      mock_value_in_store('123')
+    end
+
+    it 'returns this value as header' do
+      _, headers, _ = middleware.call(build_env(path, if_none_match))
+
+      expect(headers['ETag']).to eq 'W/"123"'
+    end
+  end
+
+  context 'when If-None-Match header matches ETag in store' do
+    let(:path) { enabled_path }
+    let(:if_none_match) { 'W/"123"' }
+
+    before do
+      mock_value_in_store('123')
+    end
+
+    it 'does not call app' do
+      expect(app).not_to receive(:call)
+
+      middleware.call(build_env(path, if_none_match))
+    end
+
+    it 'returns status code 304' do
+      status, _, _ = middleware.call(build_env(path, if_none_match))
+
+      expect(status).to eq 304
+    end
+
+    it 'tracks "etag_caching_cache_hit" event' do
+      expect(Gitlab::Metrics).to receive(:add_event)
+        .with(:etag_caching_middleware_used)
+      expect(Gitlab::Metrics).to receive(:add_event)
+        .with(:etag_caching_cache_hit)
+
+      middleware.call(build_env(path, if_none_match))
+    end
+  end
+
+  context 'when If-None-Match header does not match ETag in store' do
+    let(:path) { enabled_path }
+    let(:if_none_match) { 'W/"abc"' }
+
+    before do
+      mock_value_in_store('123')
+    end
+
+    it 'calls app' do
+      expect(app).to receive(:call).and_return([app_status_code, {}, ['body']])
+
+      middleware.call(build_env(path, if_none_match))
+    end
+
+    it 'tracks "etag_caching_resource_changed" event' do
+      mock_app_response
+
+      expect(Gitlab::Metrics).to receive(:add_event)
+        .with(:etag_caching_middleware_used)
+      expect(Gitlab::Metrics).to receive(:add_event)
+        .with(:etag_caching_resource_changed)
+
+      middleware.call(build_env(path, if_none_match))
+    end
+  end
+
+  context 'when If-None-Match header is not specified' do
+    let(:path) { enabled_path }
+
+    before do
+      mock_value_in_store('123')
+      mock_app_response
+    end
+
+    it 'tracks "etag_caching_header_missing" event' do
+      expect(Gitlab::Metrics).to receive(:add_event)
+        .with(:etag_caching_middleware_used)
+      expect(Gitlab::Metrics).to receive(:add_event)
+        .with(:etag_caching_header_missing)
+
+      middleware.call(build_env(path, if_none_match))
+    end
+  end
+
+  def mock_app_response
+    allow(app).to receive(:call).and_return([app_status_code, {}, ['body']])
+  end
+
+  def mock_value_in_store(value)
+    allow_any_instance_of(Gitlab::EtagCaching::Store)
+      .to receive(:get).and_return(value)
+  end
+
+  def build_env(path, if_none_match)
+    {
+      'PATH_INFO' => path,
+      'HTTP_IF_NONE_MATCH' => if_none_match
+    }
+  end
+end