Add test helpers for subscriber list metrics

lib/gds_api/test_helpers/email_alert_api.rb

@@ -164,6 +164,16 @@ def stub_any_email_alert_api_call
         stub_request(:any, %r{\A#{EMAIL_ALERT_API_ENDPOINT}})
       end
 
+      def stub_get_subscriber_list_metrics(path:, response:)
+        stub_request(:get, "#{EMAIL_ALERT_API_ENDPOINT}/subscriber-lists/metrics#{path}")
+          .to_return(status: 200, body: response)
+      end
+
+      def stub_get_subscriber_list_metrics_not_found(path:)
+        stub_request(:get, "#{EMAIL_ALERT_API_ENDPOINT}/subscriber-lists/metrics#{path}")
+          .to_return(status: 404)
+      end
+
       def assert_email_alert_api_content_change_created(attributes = nil)
         if attributes
           matcher = lambda do |request|

test/test_helpers/email_alert_api_test.rb

@@ -49,4 +49,24 @@
       assert_equal(2, result["subscriptions"].count)
     end
   end
+
+  describe "#stub_get_subscriber_list_metrics_not_found" do
+    it "raises 404" do
+      stub_get_subscriber_list_metrics_not_found(path: "/some/path")
+      assert_raises(GdsApi::HTTPNotFound) do
+        email_alert_api.get_subscriber_list_metrics(path: "/some/path")
+      end
+    end
+  end
+
+  describe "#stub_get_subscriber_list_metrics" do
+    it "returns the stubbed data" do
+      json = { subscriber_list_count: 3, all_notify_count: 10 }.to_json
+      stub_get_subscriber_list_metrics(path: "/some/path", response: json)
+      response = email_alert_api.get_subscriber_list_metrics(path: "/some/path")
+      expected = { "subscriber_list_count" => 3, "all_notify_count" => 10 }
+      assert_equal 200, response.code
+      assert_equal expected, response.to_h
+    end
+  end
 end