Move serializer tests into their own directory.

It'd be nice to keep some hygene here.

test/serializers/generators_test.rb

@@ -0,0 +1,59 @@
+class Foo < Rails::Application
+  if Rails.version.to_s.start_with? '4'
+    config.eager_load = false
+    config.secret_key_base = 'abc123'
+  end
+end
+
+Rails.application.load_generators
+
+require 'generators/serializer/serializer_generator'
+
+class SerializerGeneratorTest < Rails::Generators::TestCase
+  destination File.expand_path("../tmp", __FILE__)
+  setup :prepare_destination
+
+  tests Rails::Generators::SerializerGenerator
+  arguments %w(account name:string description:text business:references)
+
+  def test_generates_a_serializer
+    run_generator
+    assert_file "app/serializers/account_serializer.rb", /class AccountSerializer < ActiveModel::Serializer/
+  end
+
+  def test_generates_a_namespaced_serializer
+    run_generator ["admin/account"]
+    assert_file "app/serializers/admin/account_serializer.rb", /class Admin::AccountSerializer < ActiveModel::Serializer/
+  end
+
+  def test_uses_application_serializer_if_one_exists
+    Object.const_set(:ApplicationSerializer, Class.new)
+    run_generator
+    assert_file "app/serializers/account_serializer.rb", /class AccountSerializer < ApplicationSerializer/
+  ensure
+    Object.send :remove_const, :ApplicationSerializer
+  end
+
+  def test_uses_given_parent
+    Object.const_set(:ApplicationSerializer, Class.new)
+    run_generator ["Account", "--parent=MySerializer"]
+    assert_file "app/serializers/account_serializer.rb", /class AccountSerializer < MySerializer/
+  ensure
+    Object.send :remove_const, :ApplicationSerializer
+  end
+
+  def test_generates_attributes_and_associations
+    run_generator
+    assert_file "app/serializers/account_serializer.rb" do |serializer|
+      assert_match(/^  attributes :id, :name, :description$/, serializer)
+      assert_match(/^  has_one :business$/, serializer)
+    end
+  end
+
+  def test_with_no_attributes_does_not_add_extra_space
+    run_generator ["account"]
+    assert_file "app/serializers/account_serializer.rb" do |content|
+      assert_no_match /\n\nend/, content
+    end
+  end
+end