1 files changed, 98 insertions, 0 deletions
diff --git a/spec/models/prometheus_metric_spec.rb b/spec/models/prometheus_metric_spec.rb
new file mode 100644
index 00000000000..a83a31ae88c
--- /dev/null
+++ b/spec/models/prometheus_metric_spec.rb
@@ -0,0 +1,98 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe PrometheusMetric do
+  subject { build(:prometheus_metric) }
+  let(:other_project) { build(:project) }
+
+  it { is_expected.to belong_to(:project) }
+  it { is_expected.to validate_presence_of(:title) }
+  it { is_expected.to validate_presence_of(:query) }
+  it { is_expected.to validate_presence_of(:group) }
+
+  describe 'common metrics' do
+    using RSpec::Parameterized::TableSyntax
+
+    where(:common, :project, :result) do
+      false | other_project | true
+      false | nil           | false
+      true  | other_project | false
+      true  | nil           | true
+    end
+
+    with_them do
+      before do
+        subject.common = common
+        subject.project = project
+      end
+
+      it { expect(subject.valid?).to eq(result) }
+    end
+  end
+
+  describe '#query_series' do
+    using RSpec::Parameterized::TableSyntax
+
+    where(:legend, :type) do
+      'Some other legend' | NilClass
+      'Status Code'       | Array
+    end
+
+    with_them do
+      before do
+        subject.legend = legend
+      end
+
+      it { expect(subject.query_series).to be_a(type) }
+    end
+  end
+
+  describe '#group_title' do
+    shared_examples 'group_title' do |group, title|
+      subject { build(:prometheus_metric, group: group).group_title }
+
+      it "returns text #{title} for group #{group}" do
+        expect(subject).to eq(title)
+      end
+    end
+
+    it_behaves_like 'group_title', :business, 'Business metrics (Custom)'
+    it_behaves_like 'group_title', :response, 'Response metrics (Custom)'
+    it_behaves_like 'group_title', :system, 'System metrics (Custom)'
+  end
+
+  describe '#to_query_metric' do
+    it 'converts to queryable metric object' do
+      expect(subject.to_query_metric).to be_instance_of(Gitlab::Prometheus::Metric)
+    end
+
+    it 'queryable metric object has title' do
+      expect(subject.to_query_metric.title).to eq(subject.title)
+    end
+
+    it 'queryable metric object has y_label' do
+      expect(subject.to_query_metric.y_label).to eq(subject.y_label)
+    end
+
+    it 'queryable metric has no required_metric' do
+      expect(subject.to_query_metric.required_metrics).to eq([])
+    end
+
+    it 'queryable metric has weight 0' do
+      expect(subject.to_query_metric.weight).to eq(0)
+    end
+
+    it 'queryable metrics has query description' do
+      queries = [
+        {
+          query_range: subject.query,
+          unit: subject.unit,
+          label: subject.legend
+        }
+      ]
+
+      expect(subject.to_query_metric.queries).to eq(queries)
+    end
+  end
+end