mock Rails.env.development? using rspec

Question

I am writing a unit test using rspec.

I would like to mock Rails.env.develepment? to return true. How could I achieve this?.

I tried this

Rails.env.stub(:development?, nil).and_return(true)

it throws this error

activesupport-4.0.0/lib/active_support/string_inquirer.rb:22:in `method_missing': undefined method `any_instance' for "test":ActiveSupport::StringInquirer (NoMethodError)

Update ruby version ruby-2.0.0-p353, rails 4.0.0, rspec 2.11

describe "welcome_signup" do
    let(:mail) { Notifier.welcome_signup user }

    describe "in dev mode" do
      Rails.env.stub(:development?, nil).and_return(true)
      let(:mail) { Notifier.welcome_signup user }
      it "send an email to" do
        expect(mail.to).to eq([GlobalConstants::DEV_EMAIL_ADDRESS])
      end
    end
  end

Answer 1

There is a much better way described here: https://stackoverflow.com/a/24052647/362378

it "should do something specific for production" do 
  allow(Rails).to receive(:env) { "production".inquiry }
  #other assertions
end

This will provide all the functions like Rails.env.test? and also works if you just compare the strings like Rails.env == 'production'

Answer 2

You should stub in it, let, before blocks. Move your code there and it will work

And this code works in my tests (maybe your variant can work as well)

Rails.env.stub(:development? => true)

for example

describe "in dev mode" do
  let(:mail) { Notifier.welcome_signup user }

  before { Rails.env.stub(:development? => true) }

  it "send an email to" do
    expect(mail.to).to eq([GlobalConstants::DEV_EMAIL_ADDRESS])
  end
end