ruby--ruby/spec/ruby/core/comparable/lt_spec.rb

require_relative '../../spec_helper'
require_relative 'fixtures/classes'

describe "Comparable#<" do
  it "calls #<=> on self with other and returns true if #<=> returns any Integer less than 0" do
    a = ComparableSpecs::Weird.new(0)
    b = ComparableSpecs::Weird.new(20)

    a.should_receive(:<=>).any_number_of_times.and_return(-1)
    (a < b).should == true

    a.should_receive(:<=>).any_number_of_times.and_return(-0.1)
    (a < b).should == true

    a.should_receive(:<=>).any_number_of_times.and_return(-10000000)
    (a < b).should == true
  end

  it "returns false if calling #<=> on self returns 0 or any Integer greater than 0" do
    a = ComparableSpecs::Weird.new(0)
    b = ComparableSpecs::Weird.new(10)

    a.should_receive(:<=>).any_number_of_times.and_return(0)
    (a < b).should == false

    a.should_receive(:<=>).any_number_of_times.and_return(0.0)
    (a < b).should == false

    a.should_receive(:<=>).any_number_of_times.and_return(1.0)
    (a < b).should == false

    a.should_receive(:<=>).any_number_of_times.and_return(10000000)
    (a < b).should == false
  end

  it "raises an ArgumentError if calling #<=> on self returns nil" do
    a = ComparableSpecs::Weird.new(0)
    b = ComparableSpecs::Weird.new(20)

    a.should_receive(:<=>).any_number_of_times.and_return(nil)
    -> { (a < b) }.should raise_error(ArgumentError)
  end

  it "raises an argument error with a message containing the value" do
    -> { ("foo" < 7) }.should raise_error(ArgumentError) { |e|
      e.message.should == "comparison of String with 7 failed"
    }
  end
end