Question

How would you test this method with rspec?

def schema
  @schema ||= Schema.new(owner, schedules, hour_interval)
end

Answer 1

If felt inclined to ask “and what did you try to test it”, but here’s my answer anyway: If you’re unit testing in rspec, and you define methods to be your units, I would suggest to test it like this:

describe "schema" do
  let(:owner) { mock('owner') }
  let(:schedules) { mock('schedules') }
  let(:hour_interval) { mock('hour_interval') }
  let(:schema) { mock('schema') }
  before(:each) do
    subject.stub! :owner => owner, :schedules => schedules, :hour_interval => hour_interval
  end
  context "unmemoized" do
    it "should instantiate a new schema" do
      Schema.should_receive(:new).with(owner, schedules, hour_interval).and_return schema
      subject.schema.should == schema
    end
  end
  context "memoized" do
    it "should use the instantiated and memoized schema" do
      Schema.should_receive(:new).with(owner, schedules, hour_interval).once.and_return schema
      2.times do
        subject.schema.should == schema
      end
    end
  end
end

Like this, you test the unit and all it does in isolation.

For explanation regarding the details, look at The RSpec Documentation and/or Best RSpec Practices