1 files changed, 40 insertions, 0 deletions
diff --git a/spec/services/prometheus/adapter_service_spec.rb b/spec/services/prometheus/adapter_service_spec.rb
new file mode 100644
index 00000000000..335fc5844aa
--- /dev/null
+++ b/spec/services/prometheus/adapter_service_spec.rb
@@ -0,0 +1,40 @@
+require 'spec_helper'
+
+describe Prometheus::AdapterService do
+  let(:project) { create(:project) }
+  subject { described_class.new(project) }
+
+  describe '#prometheus_adapter' do
+    let(:cluster) { create(:cluster, :provided_by_user, environment_scope: '*', projects: [project]) }
+
+    context 'prometheus service can execute queries' do
+      let(:prometheus_service) { double(:prometheus_service, can_query?: true) }
+
+      before do
+        allow(project).to receive(:find_or_initialize_service).with('prometheus').and_return prometheus_service
+      end
+
+      it 'return prometheus service as prometheus adapter' do
+        expect(subject.prometheus_adapter).to eq(prometheus_service)
+      end
+    end
+
+    context "prometheus service can't execute queries" do
+      let(:prometheus_service) { double(:prometheus_service, can_query?: false) }
+
+      context 'with cluster with prometheus installed' do
+        let!(:prometheus) { create(:clusters_applications_prometheus, :installed, cluster: cluster) }
+
+        it 'returns application handling all environments' do
+          expect(subject.prometheus_adapter).to eq(prometheus)
+        end
+      end
+
+      context 'with cluster without prometheus installed' do
+        it 'returns nil' do
+          expect(subject.prometheus_adapter).to be_nil
+        end
+      end
+    end
+  end
+end