Add Helpers.wait_for(pid). Remove :noop call

farmbot_ext/lib/farmbot_ext/api/image_uploader.ex

@@ -44,8 +44,6 @@ defmodule FarmbotExt.API.ImageUploader do
   end
 
   def handle_continue([], state), do: {:noreply, state, @checkup_time_ms}
-  # This only exists to flush handle_cast's. I think. -RC
-  def handle_call(:noop, _, s), do: {:reply, :ok, s}
 
   # the meta here is likely inaccurate here because of pulling the location data
   # from the cache instead of from the firmware directly. It's close enough and

farmbot_ext/test/farmbot_ext/api/image_uploader_test.exs

@@ -1,4 +1,5 @@
 defmodule FarmbotExt.API.ImageUploaderTest do
+  require Helpers
   use ExUnit.Case, async: false
   use Mimic
   alias FarmbotExt.API.ImageUploader
@@ -22,12 +23,21 @@ defmodule FarmbotExt.API.ImageUploaderTest do
     end)
 
     expect(FarmbotExt.API, :upload_image, 4, fn
-      "/tmp/images/d.gif", _meta -> {:ok, %{status: 401, body: %{}}}
+      "/tmp/images/d.gif", _meta -> {:error, %{status: 401, body: %{}}}
       _image_filename, _meta -> {:ok, %{status: 201, body: %{}}}
     end)
 
+    err_msg =
+      "Upload Error (/tmp/images/d.gif): " <>
+        "{:error, %{body: %{}, status: 401}}"
+
+    Helpers.expect_log("Uploaded image: /tmp/images/a.jpg")
+    Helpers.expect_log("Uploaded image: /tmp/images/b.jpeg")
+    Helpers.expect_log("Uploaded image: /tmp/images/c.png")
+    Helpers.expect_log(err_msg)
+
     ImageUploader.force_checkup()
     send(pid, :timeout)
-    :ok = GenServer.call(pid, :noop)
+    Helpers.wait_for(pid)
   end
 end

farmbot_ext/test/test_helper.exs

@@ -19,6 +19,32 @@ System.put_env("LOG_SILENCE", "true")
 ExUnit.start(assert_receive_timeout: String.to_integer(timeout))
 
 defmodule Helpers do
+  # Maybe I don't need this?
+  # Maybe I could use `start_supervised`?
+  # https://hexdocs.pm/ex_unit/ExUnit.Callbacks.html#start_supervised/2
+
+  # Base case: We have a pid
+  def wait_for(pid) when is_pid(pid), do: continue_waiting(pid)
+  # Failure case: We failed to find a pid for a module.
+  def wait_for(nil), do: raise("Attempted to wait on bad module/pid")
+  # Edge case: We have a module and need to try finding its pid.
+  def wait_for(mod), do: wait_for(Process.whereis(mod))
+
+  defp continue_waiting(pid) do
+    wait(pid, Process.info(pid, :message_queue_len))
+  end
+
+  defp wait(_pid, {:message_queue_len, 0}), do: :ok
+
+  defp wait(pid, {:message_queue_len, n}) when n < 20 do
+    Process.sleep(100)
+    continue_waiting(pid)
+  end
+
+  defp wait(pid, {:message_queue_len, n}) do
+    raise "No longer waiting on #{inspect(pid)} after #{n} attempts"
+  end
+
   defmacro expect_log(message) do
     quote do
       expect(FarmbotCore.LogExecutor, :execute, fn log ->