If you browse the RSpec Expectations 2.99 and RSpec Expectations 2.14 and search the section - Truthiness and existentialism, you will find expect(actual).to be_true # passes if actual is truthy (not nil or false) expect(actual).to be_false # passes if actual is falsy (nil or false) # ............... # ... But of you browse RSpec Expectations 3.0 , the above method names got changed to - expect(ac