NoMethodError: undefined method 'env' for nil:NilClass in ActionMailer::TestCase

Question

I'm starting in ruby on rails and created a sample application. In this application I have a mail class and a test generated Mail class. I managed to get all tests working except the tests from ActionMailer::TestCase. Every time I run the tests I get an error message:

NoMethodError: undefined method 'env' for nil:NilClass.

My generated mailer test method looks like this:

test "new_project" do
    mail = ProjectMailer.new_project
    assert_equal "New project", mail.subject
    assert_equal ["to@example.org"], mail.to
    assert_equal ["from@example.com"], mail.from
    assert_match "Hi", mail.body.encoded
end

I have in my test_helper

class ActionController::TestCase
  include Devise::TestHelpers
end

class ActionMailer::TestCase
      include Devise::TestHelpers
    end

class ActiveSupport::TestCase
  ActiveRecord::Migration.check_pending!

  include Devise::TestHelpers
  fixtures :all
end

Anyone does know how to solve that?

Answer 1

You're including Devise::TestHelpers. You should create specific test_helper for tests, that really need Devise.

Same question on stackoverflow.

undefined method 'env' for nil:NilClass