require File.expand_path('../../../spec_helper', __FILE__)

describe "Integer#lcm" do
  ruby_version_is "1.9" do
    it "returns self if equal to the argument" do
      1.lcm(1).should == 1
      398.lcm(398).should == 398
    end

    it "returns an Integer" do
      36.lcm(6).should be_kind_of(Integer)
      4.lcm(20981).should be_kind_of(Integer)
    end

    it "returns the least common multiple of self and argument" do
      200.lcm(2001).should == 400200
      99.lcm(90).should == 990
    end

    it "returns a positive integer even if self is negative" do
      -12.lcm(6).should == 12
      -100.lcm(100).should == 100
    end

    it "returns a positive integer even if the argument is negative" do
      12.lcm(-6).should == 12
      100.lcm(-100).should == 100
    end

    it "returns a positive integer even if both self and argument are negative" do
      -12.lcm(-6).should == 12
      -100.lcm(-100).should == 100
    end

    it "accepts a Bignum argument" do
      bignum = 9999**99
      bignum.should be_kind_of(Bignum)
      99.lcm(bignum).should == bignum
    end

    it "works if self is a Bignum" do
      bignum = 9999**99
      bignum.should be_kind_of(Bignum)
      bignum.lcm(99).should == bignum
    end

    it "raises an ArgumentError if not given an argument" do
      lambda { 12.lcm }.should raise_error(ArgumentError)
    end

    it "raises an ArgumentError if given more than one argument" do
      lambda { 12.lcm(30, 20) }.should raise_error(ArgumentError)
    end

    it "raises an TypeError unless the argument is an Integer" do
      lambda { 39.lcm(3.8)   }.should raise_error(TypeError)
      lambda { 45872.lcm([]) }.should raise_error(TypeError)
    end
  end
end
