add basic mailer spec features

Author: JonRowe

features/mailer_specs/mailer_spec.feature

@@ -0,0 +1,53 @@
+Feature: mailer spec
+
+  @rails_post_5
+  Scenario: simple passing example
+    Given a file named "spec/mailers/notifications_mailer_spec.rb" with:
+      """ruby
+      require "rails_helper"
+
+      RSpec.describe NotificationsMailer, :type => :mailer do
+        describe "notify" do
+          let(:mail) { NotificationsMailer.signup }
+
+          it "renders the headers" do
+            expect(mail.subject).to eq("")
+            expect(mail.to).to eq(["[email protected]"])
+            expect(mail.from).to eq(["[email protected]"])
+          end
+
+          it "renders the body" do
+            expect(mail.body.encoded).to match("Hi")
+          end
+        end
+      end
+      """
+    When I run `rspec spec`
+    Then the example should pass
+
+  @rails_pre_5
+  Scenario: using URL helpers without default options
+    Given a file named "config/initializers/mailer_defaults.rb" with:
+      """ruby
+      # no default options
+      """
+    And a file named "spec/mailers/notifications_spec.rb" with:
+      """ruby
+      require 'rails_helper'
+
+      RSpec.describe Notifications, :type => :mailer do
+        let(:mail) { Notifications.signup }
+
+        it "renders the headers" do
+          expect(mail.subject).to eq("Signup")
+          expect(mail.to).to eq(["[email protected]"])
+          expect(mail.from).to eq(["[email protected]"])
+        end
+
+        it 'renders the body' do
+          expect(mail.body.encoded).to match("Hi")
+        end
+      end
+      """
+    When I run `rspec spec`
+    Then the examples should all pass