add mix task for tests, mocks and integration

Added mix task to generate test file for the gateways, add
a file to define the mock responses and also to generate
integration test.

lib/mix/new.ex

@@ -76,14 +76,21 @@ Comma separated list of required configuration keys:
       gateway_module: module_name,
       gateway_underscore: Macro.underscore(name),
       required_config_keys: required_keys,
-      gateway_url: url
+      gateway_url: url,
+      gateway_mock_test: Macro.underscore(name) <> "_test",
+      gateway_mock_response: Macro.underscore(name) <> "_mock",
     ]
 
     if (Mix.Shell.IO.yes? "\nDoes this look good?\n#{inspect(bindings, pretty: true)}\n>") do
       gateway = EEx.eval_file("templates/gateway.eex", bindings)
-      # mock = ""
-      # integration = ""
+      mock = EEx.eval_file("templates/test.eex", bindings)
+      mock_response = EEx.eval_file("templates/mock_response.eex", bindings)
+      integration = EEx.eval_file("templates/integration.eex", bindings)
+
       create_file("lib/gringotts/gateways/#{bindings[:gateway_underscore]}.ex", gateway)
+      create_file("test/gateways/#{bindings[:gateway_mock_test]}.exs", mock)
+      create_file("test/mocks/#{bindings[:gateway_mock_response]}.exs", mock_response)
+      create_file("test/integration/gateways/#{bindings[:gateway_mock_test]}.exs", integration)      
     else
       Mix.Shell.IO.info("Doing nothing, bye!")
     end

templates/integration.eex

@@ -0,0 +1,36 @@
+defmodule Gringotts.Integration.Gateways.<%= gateway_module <> "Test"%> do
+  # Integration tests for the <%= gateway_module%> 
+
+  use ExUnit.Case, async: false
+  alias Gringotts.Gateways.<%= gateway_module%>
+
+  @moduletag :integration
+
+  setup_all do
+    Application.put_env(:gringotts, Gringotts.Gateways.<%= gateway_module%>,
+      [
+        adapter: Gringotts.Gateways.<%= gateway_module%><%= if required_config_keys != [] do %><%= for key <- Enum.intersperse(required_config_keys, ",") do %><%= if key === "," do %><%= "#{key}" %><%= else %>
+        <%= "#{key}" %>: "your_secret_<%= "#{key}" %>"<% end %><% end %><% end %>
+      ]
+    )
+  end
+
+  # Group the test cases by public api
+  describe "purchase" do
+  end
+
+  describe "authorize" do
+  end
+
+  describe "capture" do 
+  end
+
+  describe "void" do
+  end
+
+  describe "refund" do
+  end
+
+  describe "environment setup" do
+  end
+end

templates/mock_response.eex

@@ -0,0 +1,9 @@
+defmodule Gringotts.Gateways.<%= gateway_module <> "Mock"%> do
+
+  # The module should include mock responses for test cases in <%= gateway_mock_test <> ".exs"%>.
+  # e.g. 
+  # def successful_purchase do 
+  #  {:ok, %HTTPoison.Response{body: ~s[{data: "successful_purchase"}]}
+  # end
+
+end

templates/test.eex

@@ -0,0 +1,32 @@
+defmodule Gringotts.Gateways.<%= gateway_module <> "Test" %> do
+  # The file contains mocked tests for <%= gateway_module%>
+
+  # We recommend using [mock][1] for this, you can place the mock responses from
+  # the Gateway in `test/mocks/<%= gateway_mock_response%>.exs` file, which has also been
+  # generated for you.
+  #
+  # [1]: https://github.com/jjh42/mock
+
+  # Load the mock response file before running the tests.
+  Code.require_file "../mocks/<%= gateway_mock_response <> ".exs"%>", __DIR__
+
+  use ExUnit.Case, async: false
+  alias Gringotts.Gateways.<%= gateway_module%>
+  import Mock
+
+  # Group the test cases by public api
+  describe "purchase" do
+  end
+
+  describe "authorize" do
+  end
+
+  describe "capture" do 
+  end
+
+  describe "void" do
+  end
+
+  describe "refund" do
+  end
+end