make api_key overridable in Application env

lib/open_states/application.ex

@@ -7,8 +7,7 @@ defmodule OpenStates.Application do
   use Receiver, as: :credentials
 
   def start(_type, _args) do
-    api_key = Application.get_env(:open_states, :api_key, System.get_env("OPENSTATES_API_KEY"))
-    start_credentials(fn -> api_key end)
+    set_api_key_from_env()
 
     children = []
 
@@ -18,4 +17,11 @@ defmodule OpenStates.Application do
 
   @spec api_key() :: String.t()
   def api_key, do: get_credentials()
+
+  @spec set_api_key_from_env() :: :ok
+  def set_api_key_from_env do
+    start_credentials()
+    api_key = Application.get_env(:open_states, :api_key, System.get_env("OPENSTATES_API_KEY"))
+    update_credentials(fn _ -> api_key end)
+  end
 end

test/open_states_test.exs

@@ -1,5 +1,5 @@
 defmodule OpenStatesTest do
-  use ExUnit.Case, async: true
+  use ExUnit.Case, async: false
   import Mock
   doctest OpenStates
 
@@ -11,6 +11,19 @@ defmodule OpenStatesTest do
     assert OpenStates.api_key() == System.get_env("OPENSTATES_API_KEY")
   end
 
+  test "api_key/0 can be overriden in Application config" do
+    original = OpenStates.api_key()
+    Application.put_env(:open_states, :api_key, "hello")
+    :ok = OpenStates.Application.set_api_key_from_env()
+
+    assert OpenStates.api_key() == "hello"
+
+    Application.put_env(:open_states, :api_key, original)
+    :ok = OpenStates.Application.set_api_key_from_env()
+
+    assert OpenStates.api_key() == original
+  end
+
   test "headers/0 returns the API query headers" do
     assert OpenStates.headers() == ["X-API-KEY": OpenStates.api_key()]
   end