Improve tests

lib/thousand_island/listener.ex

@@ -32,14 +32,15 @@ defmodule ThousandIsland.Listener do
            ),
          {:ok, {ip, port}} <-
            server_config.transport_module.sockname(listener_socket) do
-      span_meta = %{
+      span_metadata = %{
+        handler: server_config.handler_module,
         local_address: ip,
         local_port: port,
         transport_module: server_config.transport_module,
         transport_options: server_config.transport_options
       }
 
-      listener_span = ThousandIsland.Telemetry.start_span(:listener, %{}, span_meta)
+      listener_span = ThousandIsland.Telemetry.start_span(:listener, %{}, span_metadata)
 
       {:ok,
        %{listener_socket: listener_socket, local_info: {ip, port}, listener_span: listener_span}}

lib/thousand_island/telemetry.ex

@@ -332,7 +332,9 @@ defmodule ThousandIsland.Telemetry do
   @spec start_child_span(t(), span_name(), measurements(), metadata()) :: t()
   def start_child_span(parent_span, span_name, measurements \\ %{}, metadata \\ %{}) do
     metadata =
-      Map.put(metadata, :parent_telemetry_span_context, parent_span.telemetry_span_context)
+      metadata
+      |> Map.put(:parent_telemetry_span_context, parent_span.telemetry_span_context)
+      |> Map.put(:handler, parent_span.start_metadata.handler)
 
     start_span(span_name, measurements, metadata)
   end
@@ -361,7 +363,11 @@ defmodule ThousandIsland.Telemetry do
   @spec untimed_span_event(t(), event_name() | untimed_event_name(), measurements(), metadata()) ::
           :ok
   def untimed_span_event(span, name, measurements \\ %{}, metadata \\ %{}) do
-    metadata = Map.put(metadata, :telemetry_span_context, span.telemetry_span_context)
+    metadata =
+      metadata
+      |> Map.put(:telemetry_span_context, span.telemetry_span_context)
+      |> Map.put(:handler, span.start_metadata.handler)
+
     event([span.span_name, name], measurements, metadata)
   end
 

test/support/telemetry_helpers.ex

@@ -0,0 +1,34 @@
+defmodule TelemetryHelpers do
+  @moduledoc false
+
+  @events [
+    [:thousand_island, :listener, :start],
+    [:thousand_island, :listener, :stop],
+    [:thousand_island, :acceptor, :start],
+    [:thousand_island, :acceptor, :stop],
+    [:thousand_island, :acceptor, :spawn_error],
+    [:thousand_island, :acceptor, :econnaborted],
+    [:thousand_island, :connection, :start],
+    [:thousand_island, :connection, :stop],
+    [:thousand_island, :connection, :ready],
+    [:thousand_island, :connection, :async_recv],
+    [:thousand_island, :connection, :recv],
+    [:thousand_island, :connection, :recv_error],
+    [:thousand_island, :connection, :send],
+    [:thousand_island, :connection, :send_error],
+    [:thousand_island, :connection, :sendfile],
+    [:thousand_island, :connection, :sendfile_error],
+    [:thousand_island, :connection, :socket_shutdown]
+  ]
+
+  def attach_all_events(handler) do
+    ref = make_ref()
+    _ = :telemetry.attach_many(ref, @events, &__MODULE__.handle_event/4, {self(), handler})
+    fn -> :telemetry.detach(ref) end
+  end
+
+  def handle_event(event, measurements, %{handler: handler} = metadata, {pid, handler}),
+    do: send(pid, {:telemetry, event, measurements, metadata})
+
+  def handle_event(_event, _measurements, _metadata, {_pid, _handler}), do: :ok
+end