test feature flag

test/event_type_test.exs

@@ -1,9 +1,12 @@
-defmodule OpentelemetryAbsintheTest.EvenType do
+defmodule OpentelemetryAbsintheTest.EventTypeTest do
   use OpentelemetryAbsintheTest.Case
 
+  alias OpentelemetryAbsintheTest.Support.Counter
   alias OpentelemetryAbsintheTest.Support.GraphQL.Queries
   alias OpentelemetryAbsintheTest.Support.Query
 
+  alias OpentelemetryAbsintheTest.EventTypeTest.TelemetryProvider
+
   @graphql_event_type :"graphql.event.type"
 
   doctest OpentelemetryAbsinthe.Instrumentation
@@ -17,5 +20,57 @@ defmodule OpentelemetryAbsintheTest.EvenType do
     assert :operation == Map.get(attributes, @graphql_event_type)
   end
 
-  # NOTE: a subscription test could go here, but setting up subscription testing just for this didn't seem worth it
+  describe "subscription" do
+    test "doesn't attach to subscription if not enabled" do
+      Application.put_env(:opentelemetry_absinthe, :telemetry_provider, TelemetryProvider)
+
+      on_exit(fn ->
+        Application.put_env(:opentelemetry_absinthe, :telemetry_provider, :telemetry)
+      end)
+
+      {:ok, _} = TelemetryProvider.start_link([])
+
+      OpentelemetryAbsinthe.Instrumentation.setup()
+
+      # Attaches only to operation start/stop
+      assert 2 == TelemetryProvider.count()
+    end
+
+    test "attaches to subscription if enabled" do
+      Application.put_env(:opentelemetry_absinthe, :telemetry_provider, TelemetryProvider)
+
+      on_exit(fn ->
+        Application.put_env(:opentelemetry_absinthe, :telemetry_provider, :telemetry)
+      end)
+
+      {:ok, _} = TelemetryProvider.start_link([])
+
+      OpentelemetryAbsinthe.Instrumentation.setup(trace_subscriptions: true)
+
+      # Attaches also to subscription start/stop
+      assert 4 == TelemetryProvider.count()
+    end
+  end
+end
+
+defmodule OpentelemetryAbsintheTest.EventTypeTest.TelemetryProvider do
+  use Agent
+
+  @me __MODULE__
+
+  def start_link(_opts) do
+    Agent.start_link(fn -> 0 end, name: @me)
+  end
+
+  def count() do
+    Agent.get(@me, & &1)
+  end
+
+  defp increment() do
+    Agent.update(@me, &(&1 + 1))
+  end
+
+  def attach(_, _, _, _) do
+    increment()
+  end
 end