From 871c520316dae452d087e34d63c3266cbbfa3719 Mon Sep 17 00:00:00 2001
From: "Paulo F. Oliveira" <paulo.ferraz.oliveira@gmail.com>
Date: Thu, 13 Jun 2024 19:04:04 +0100
Subject: [PATCH] Return `{:error, :already_mocked}` when using `new/1,2` over
 mock (#25)

---
 lib/nuntiux.ex        | 13 +++++++++++--
 test/nuntiux_test.exs |  9 +++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/lib/nuntiux.ex b/lib/nuntiux.ex
index 119b0ba..85f32d4 100644
--- a/lib/nuntiux.ex
+++ b/lib/nuntiux.ex
@@ -89,9 +89,15 @@ defmodule Nuntiux do
         when process_name: process_name(),
              opts: opts(),
              ok: :ok,
-             error: {:error, :not_found}
+             error: {:error, :not_found | :already_mocked}
   def new(process_name, opts \\ %{}) do
-    Nuntiux.Supervisor.start_mock(process_name, opts)
+    case mocked_process(process_name) do
+      {:error, :not_mocked} ->
+        Nuntiux.Supervisor.start_mock(process_name, opts)
+
+      _pid ->
+        {:error, :already_mocked}
+    end
   end
 
   @doc """
@@ -105,6 +111,9 @@ defmodule Nuntiux do
       {:error, :not_found} ->
         raise(Nuntiux.Exception, message: "Process #{process_name} not found.")
 
+      {:error, :already_mocked} ->
+        raise(Nuntiux.Exception, message: "Process #{process_name} is already mocked.")
+
       :ok ->
         process_name
     end
diff --git a/test/nuntiux_test.exs b/test/nuntiux_test.exs
index 2a48f10..2988ac0 100644
--- a/test/nuntiux_test.exs
+++ b/test/nuntiux_test.exs
@@ -476,6 +476,15 @@ defmodule NuntiuxTest do
       assert captured_log =~ "expect_id: :no_head_matches"
       assert captured_log =~ ":function_clause"
     end
+
+    test "new!/1 raises an exception if trying to mock a mock", %{
+      plus_oner_name: plus_oner_name
+    } do
+      assert_raise(Nuntiux.Exception, ~r/^Process .* is already mocked\.$/, fn ->
+        Nuntiux.new!(plus_oner_name)
+        Nuntiux.new!(plus_oner_name)
+      end)
+    end
   end
 
   defp send2(dest, msg) do