fix tests

lib/memex/accounts.ex

@@ -117,6 +117,8 @@ defmodule Memex.Accounts do
       :passed
 
   """
+  @spec register_user(attrs :: map()) ::
+          {:ok, User.t()} | {:error, :invalid_token | User.changeset()}
   @spec register_user(attrs :: map(), Invite.token() | nil) ::
           {:ok, User.t()} | {:error, :invalid_token | User.changeset()}
   def register_user(attrs, invite_token \\ nil) do

lib/memex/accounts/invites.ex

@@ -85,7 +85,9 @@ defmodule Memex.Accounts.Invites do
     end
   end
 
-  @spec get_invite_by_token(Invite.token()) :: {:ok, Invite.t()} | {:error, :invalid_token}
+  @spec get_invite_by_token(Invite.token() | nil) :: {:ok, Invite.t()} | {:error, :invalid_token}
+  defp get_invite_by_token(token) when token in [nil, ""], do: {:error, :invalid_token}
+
   defp get_invite_by_token(token) do
     Repo.one(
       from i in Invite,