1 files changed, 77 insertions, 0 deletions
diff --git a/spec/lib/gitlab/metrics/dashboard/stages/variable_endpoint_inserter_spec.rb b/spec/lib/gitlab/metrics/dashboard/stages/variable_endpoint_inserter_spec.rb
new file mode 100644
index 00000000000..9303ff981fb
--- /dev/null
+++ b/spec/lib/gitlab/metrics/dashboard/stages/variable_endpoint_inserter_spec.rb
@@ -0,0 +1,77 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Metrics::Dashboard::Stages::VariableEndpointInserter do
+  include MetricsDashboardHelpers
+
+  let(:project) { build_stubbed(:project) }
+  let(:environment) { build_stubbed(:environment, project: project) }
+
+  describe '#transform!' do
+    subject(:transform!) { described_class.new(project, dashboard, environment: environment).transform! }
+
+    let(:dashboard) { load_sample_dashboard.deep_symbolize_keys }
+
+    context 'when dashboard variables are present' do
+      it 'assigns prometheus_endpoint_path to metric_label_values variable type' do
+        endpoint_path = Gitlab::Routing.url_helpers.prometheus_api_project_environment_path(
+          project,
+          environment,
+          proxy_path: :series,
+          match: ['backend:haproxy_backend_availability:ratio{env="{{env}}"}']
+        )
+
+        transform!
+
+        expect(
+          dashboard.dig(:templating, :variables, :metric_label_values_variable, :options)
+        ).to include(prometheus_endpoint_path: endpoint_path)
+      end
+
+      it 'does not modify other variable types' do
+        original_text_variable = dashboard[:templating][:variables][:text_variable_full_syntax].deep_dup
+
+        transform!
+
+        expect(dashboard[:templating][:variables][:text_variable_full_syntax]).to eq(original_text_variable)
+      end
+
+      context 'when variable does not have the required series_selector' do
+        it 'adds prometheus_endpoint_path without match parameter' do
+          dashboard[:templating][:variables][:metric_label_values_variable][:options].delete(:series_selector)
+          endpoint_path = Gitlab::Routing.url_helpers.prometheus_api_project_environment_path(
+            project,
+            environment,
+            proxy_path: :series
+          )
+
+          transform!
+
+          expect(
+            dashboard.dig(:templating, :variables, :metric_label_values_variable, :options)
+          ).to include(prometheus_endpoint_path: endpoint_path)
+        end
+      end
+    end
+
+    context 'when no variables are present' do
+      it 'does not fail' do
+        dashboard.delete(:templating)
+
+        expect { transform! }.not_to raise_error
+      end
+    end
+
+    context 'with no environment' do
+      subject(:transform!) { described_class.new(project, dashboard, {}).transform! }
+
+      it 'raises error' do
+        expect { transform! }.to raise_error(
+          Gitlab::Metrics::Dashboard::Errors::DashboardProcessingError,
+          'Environment is required for Stages::VariableEndpointInserter'
+        )
+      end
+    end
+  end
+end