expect actionmailer base nullmail

The "expect" method in Ruby is a way to define expectations for the behavior of an object or method. In this case, we are using it to specify the behavior of the "ActionMailer::Base" class when it is passed a "NullMail" object.

Here are the steps to achieve this:

1. First, make sure you have the necessary dependencies installed. You will need the Action Mailer gem, which can be added to your Gemfile or installed directly using the command: gem install actionmailer.

2. Once you have the Action Mailer gem installed, you can start by creating an Action Mailer class. This class will inherit from the "ActionMailer::Base" class. For example, you can create a file called "my_mailer.rb" and define your class as follows:

class MyMailer < ActionMailer::Base
  # Define your mailer methods here
end

1. Next, you will define a mailer method that will use the "NullMail" object. A "NullMail" object is a special kind of mail object that doesn't actually send emails but can be useful for testing or other purposes where you don't want to send real emails. For example, you can define a method called "null_email" in your mailer class:

class MyMailer < ActionMailer::Base
  def null_email
    mail(to: '[email protected]', subject: 'Null Email')
  end
end

1. Now, to test the behavior of your mailer class using the "NullMail" object, you can use the "expect" method. This method allows you to define expectations for the behavior of an object or method. In this case, you want to expect that when you call the "null_email" method on your mailer class, it will return a "NullMail" object. Here is an example of how you can use the "expect" method:

RSpec.describe MyMailer do
  describe '#null_email' do
    it 'returns a NullMail object' do
      expect(MyMailer.null_email).to be_a(NullMail)
    end
  end
end

1. Finally, you can run your tests to verify that the behavior of your mailer class meets your expectations. You can use a testing framework like RSpec to run your tests. Make sure you have RSpec installed, and then you can run your tests using the command: rspec my_mailer_spec.rb.

By following these steps, you should be able to use the "expect" method to define expectations for the behavior of the "ActionMailer::Base" class when it is passed a "NullMail" object. This can be useful for testing or other scenarios where you want to control the behavior of Action Mailer in your Ruby application.