From 8d87a8aefa2ddaa71c0954d1b201632b95e9d88f Mon Sep 17 00:00:00 2001
From: Maciej Kaszubowski <maciej@mkaszubowski.pl>
Date: Fri, 13 Oct 2017 12:58:37 +0200
Subject: [PATCH] Check if Mix is present before using Mix.env()

---
 lib/mockery.ex | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/lib/mockery.ex b/lib/mockery.ex
index 6fc9b02..1c888f9 100644
--- a/lib/mockery.ex
+++ b/lib/mockery.ex
@@ -35,7 +35,7 @@ defmodule Mockery do
     module | proxy
   def of(mod, opts \\ []) when is_atom(mod)
                           when is_binary(mod) do
-    env = opts[:env] || Mix.env
+    env = opts[:env] || mix_env()
 
     if env != :test do
       to_mod(mod)
@@ -107,4 +107,8 @@ defmodule Mockery do
 
     mod
   end
+
+  defp mix_env do
+    if Kernel.function_exported?(Mix, :env, 0), do: Mix.env(), else: :prod
+  end
 end