How do you create an rspec testing for a self.method?

Question

I currently have this method in my User class:

def self.authenticate(email, password)
  user = User.find_by_email(email)
  (user && user.has_password?(password)) ? user : nil
end

How do I run rspec testing on this?

I tried to run it { responds_to(:authenticate) }, but I assume the self thing is different from the authenticate.

I am still a beginner at rails and any tips on how to test and explanation on the self keyword will be much appreciated!

Answer 1

describe User do
  let(:user) { User.create(:email => "[email protected]", :password => "foo") }

  it "authenticates existing user" do
    User.authenticate(user.email, user.password).should eq(user)
  end

  it "does not authenticate user with wrong password" do
    User.authenticate(user.email, "bar").should be_nil
  end
end

Answer 2

@depa's answer is good, but for the sake of alternatives and because I prefer the shorter syntax:

describe User do
  let(:user) { User.create(:email => email, :password => password) }

  describe "Authentication" do
    subject { User.authenticate(user.email, user.password) }

    context "Given an existing user" do
      let(:email) { "[email protected]" }
      context "With a correct password" do
        let(:password) { "foo" }
        it { should eq(user) }
      end
      context "With an incorrect password" do
        let(:password) { "bar" }
        it { should be_nil }
      end
    end
  end
end

Aside from my preference for the sytax, I believe this has 2 major benefits over the other style:

• It makes it easier to override certain values (as I've done with password above)
• More importantly, it highlights what hasn't been tested, e.g. a blank password, an user that doesn't exist etc.

That's why the combination of using context and subject and let is, for me, far superior to the usual style.