chore(tests): remove key from test config (#24)

README.md

@@ -70,11 +70,11 @@ Tests are written using [ExUnit](https://hexdocs.pm/ex_unit/ExUnit.html), Elixir
 
 Here's how you can run the tests:
 
-    mix test
+    LOB_API_KEY=YOUR_TEST_API_KEY mix test
 
 To run tests with a coverage report:
 
-    mix coveralls.html
+    LOB_API_KEY=YOUR_TEST_API_KEY mix coveralls.html
 
 Then view the report at `cover/excoveralls.html`.
 

config/test.exs

@@ -1,4 +1,4 @@
 use Mix.Config
 
 config :lob_elixir,
-  api_key: "test_5fae9e2d112690f0f8d534c5f9b4ad10257"
+  api_key: System.get_env("LOB_API_KEY")

test/lob/client_test.exs

@@ -13,9 +13,14 @@ defmodule Lob.ClientTest do
   describe "api_key/1" do
 
     test "raises MissingAPIKeyError if no API key is found" do
+
       assert_raise(MissingAPIKeyError, fn ->
+        api_key = System.get_env("LOB_API_KEY")
+        System.delete_env("LOB_API_KEY")
         Client.api_key(nil)
+        System.put_env("LOB_API_KEY", api_key)
       end)
+
     end
 
   end