ruby--ruby/spec/ruby/core/integer/comparison_spec.rb

require_relative '../../spec_helper'

describe "Integer#<=>" do
  context "fixnum" do
    it "returns -1 when self is less than the given argument" do
      (-3 <=> -1).should == -1
      (-5 <=> 10).should == -1
      (-5 <=> -4.5).should == -1
    end

    it "returns 0 when self is equal to the given argument" do
      (0 <=> 0).should == 0
      (954 <=> 954).should == 0
      (954 <=> 954.0).should == 0
    end

    it "returns 1 when self is greater than the given argument" do
      (496 <=> 5).should == 1
      (200 <=> 100).should == 1
      (51 <=> 50.5).should == 1
    end

    it "returns nil when the given argument is not an Integer" do
      (3 <=> mock('x')).should == nil
      (3 <=> 'test').should == nil
    end
  end

  context "bignum" do
    describe "with a Fixnum" do
      it "returns -1 when other is larger" do
        (-bignum_value <=> 2).should == -1
      end

      it "returns 1 when other is smaller" do
        (bignum_value <=> 2).should == 1
      end
    end

    describe "with a Bignum" do
      describe "when other is negative" do
        it "returns -1 when self is negative and other is larger" do
          (-bignum_value(42) <=> -bignum_value).should == -1
        end

        it "returns 0 when other is equal" do
          (-bignum_value <=> -bignum_value).should == 0
        end

        it "returns 1 when self is negative and other is smaller" do
          (-bignum_value <=> -bignum_value(94)).should == 1
        end

        it "returns 1 when self is positive" do
          (bignum_value <=> -bignum_value).should == 1
        end
      end

      describe "when other is positive" do
        it "returns -1 when self is negative" do
          (-bignum_value <=> bignum_value).should == -1
        end

        it "returns -1 when self is positive and other is larger" do
          (bignum_value <=> bignum_value(38)).should == -1
        end

        it "returns 0 when other is equal" do
          (bignum_value <=> bignum_value).should == 0
        end

        it "returns 1 when other is smaller" do
          (bignum_value(56) <=> bignum_value).should == 1
        end
      end
    end

    describe "with a Float" do
      describe "when other is negative" do
        it "returns -1 when self is negative and other is larger" do
          (-bignum_value(0xffff) <=> -bignum_value.to_f).should == -1
        end

        it "returns 0 when other is equal" do
          (-bignum_value <=> -bignum_value.to_f).should == 0
        end

        it "returns 1 when self is negative and other is smaller" do
          (-bignum_value <=> -bignum_value(0xffef).to_f).should == 1
        end

        it "returns 1 when self is positive" do
          (bignum_value <=> -bignum_value.to_f).should == 1
        end
      end

      describe "when other is positive" do
        it "returns -1 when self is negative" do
          (-bignum_value <=> bignum_value.to_f).should == -1
        end

        it "returns -1 when self is positive and other is larger" do
          (bignum_value <=> bignum_value(0xfffe).to_f).should == -1
        end

        it "returns 0 when other is equal" do
          (bignum_value <=> bignum_value.to_f).should == 0
        end

        it "returns 1 when other is smaller" do
          (bignum_value(0xfeff) <=> bignum_value.to_f).should == 1
        end
      end
    end

    describe "with an Object" do
      before :each do
        @big = bignum_value
        @num = mock("value for Integer#<=>")
      end

      it "calls #coerce on other" do
        @num.should_receive(:coerce).with(@big).and_return([@big.to_f, 2.5])
        @big <=> @num
      end

      it "lets the exception go through if #coerce raises an exception" do
        @num.should_receive(:coerce).with(@big).and_raise(RuntimeError.new("my error"))
        -> {
          @big <=> @num
        }.should raise_error(RuntimeError, "my error")
      end

      it "raises an exception if #coerce raises a non-StandardError exception" do
        @num.should_receive(:coerce).with(@big).and_raise(Exception)
        -> { @big <=> @num }.should raise_error(Exception)
      end

      it "returns nil if #coerce does not return an Array" do
        @num.should_receive(:coerce).with(@big).and_return(nil)
        (@big <=> @num).should be_nil
      end

      it "returns -1 if the coerced value is larger" do
        @num.should_receive(:coerce).with(@big).and_return([@big, bignum_value(10)])
        (@big <=> @num).should == -1
      end

      it "returns 0 if the coerced value is equal" do
        @num.should_receive(:coerce).with(@big).and_return([@big, bignum_value])
        (@big <=> @num).should == 0
      end

      it "returns 1 if the coerced value is smaller" do
        @num.should_receive(:coerce).with(@big).and_return([@big, 22])
        (@big <=> @num).should == 1
      end
    end

    # The tests below are taken from matz's revision 23730 for Ruby trunk
    it "returns 1 when self is Infinity and other is a Bignum" do
      (infinity_value <=> Float::MAX.to_i*2).should == 1
    end

    it "returns -1 when self is negative and other is Infinity" do
      (-Float::MAX.to_i*2 <=> infinity_value).should == -1
    end

    it "returns 1 when self is negative and other is -Infinity" do
      (-Float::MAX.to_i*2 <=> -infinity_value).should == 1
    end

    it "returns -1 when self is -Infinity and other is negative" do
      (-infinity_value <=> -Float::MAX.to_i*2).should == -1
    end
  end
end