Tracing and asserting function calls

Questions & Help Questions
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2

I now ended up with the following helper for my ExUnit.Cases:

def setup_trace(%{trace: mfas}) when is_list(mfas) do
  :dbg.start()
  :dbg.tracer()
  :dbg.p(:all, :c)

  Enum.each(mfas, fn {mod, fun, arity} -> :dbg.tp(mod, fun, arity, []) end)

  on_exit(fn ->
    :dbg.stop()
  end)
end

def setup_trace(%{trace: mfa}), do: setup_trace(%{trace: [mfa]})

def setup_trace(_tags), do: :ok

This allows me to tag my tests:

@tag trace: {MyApp.Posts, :get_posts, 1}
test "renders list of posts", %{user: user, conn: conn} do
  # ...
end

This is better than nothing as it allows me to at least visually see multiple calls of my functions. I will maybe investigate a little bit more to check if I can come up with custom assertions.