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

Question

I start with ruby ​​on rails and create an example application. In this application, I have a mail class and a test Mail class. I managed to get all the tests except the tests from ActionMailer :: TestCase. Every time I run tests, an error message appears:

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

My mail verification method is as follows:

test "new_project" do
    mail = ProjectMailer.new_project
    assert_equal "New project", mail.subject
    assert_equal ["[e-mail]"], mail.to
    assert_equal ["[e-mail]"], mail.from
    assert_match "Hi", mail.body.encoded
end

I have in 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

Does anyone know how to solve this?

Answer 1

Devise::TestHelpers. test_helper , .

stackoverflow.

undefined 'env' nil: NilClass

: Devise, .