require_relative '../../spec_helper'
require 'bigdecimal'

describe "BigDecimal#<" do
  before :each do
    @zero = BigDecimal("0")
    @zero_pos = BigDecimal("+0")
    @zero_neg = BigDecimal("-0")
    @mixed = BigDecimal("1.23456789")
    @pos_int = BigDecimal("2E5555")
    @neg_int = BigDecimal("-2E5555")
    @pos_frac = BigDecimal("2E-9999")
    @neg_frac = BigDecimal("-2E-9999")

    @int_mock = mock('123')
    class << @int_mock
      def coerce(other)
        return [other, BigDecimal('123')]
      end
      def <(other)
        BigDecimal('123') < other
      end
    end

    @values = [@mixed, @pos_int, @neg_int, @pos_frac, @neg_frac,
      -2**32, -2**31, -2**30, -2**16, -2**8, -100, -10, -1,
      @zero , 1, 2, 10, 10.5, 2**8, 2**16, 2**32, @int_mock, @zero_pos, @zero_neg]

    @infinity = BigDecimal("Infinity")
    @infinity_neg = BigDecimal("-Infinity")

    @float_infinity = Float::INFINITY
    @float_infinity_neg = -Float::INFINITY

    @nan = BigDecimal("NaN")
  end

  it "returns true if a < b" do
    one = BigDecimal("1")
    two = BigDecimal("2")
    frac_1 = BigDecimal("1E-99999")
    frac_2 = BigDecimal("0.9E-99999")
    (@zero < one).should == true
    (two < @zero).should == false
    (frac_2 < frac_1).should == true
    (@neg_int < @pos_int).should == true
    (@pos_int < @neg_int).should == false
    (@neg_int < @pos_frac).should == true
    (@pos_frac < @neg_int).should == false
    (@zero < @zero_pos).should == false
    (@zero < @zero_neg).should == false
    (@zero_neg < @zero_pos).should == false
    (@zero_pos < @zero_neg).should == false
  end

  it "properly handles infinity values" do
    @values.each { |val|
      (val < @infinity).should == true
      (@infinity < val).should == false
      (val < @infinity_neg).should == false
      (@infinity_neg < val).should == true
    }
    (@infinity < @infinity).should == false
    (@infinity_neg < @infinity_neg).should == false
    (@infinity < @infinity_neg).should == false
    (@infinity_neg < @infinity).should == true
  end

  it "properly handles Float infinity values" do
    @values.each { |val|
      (val < @float_infinity).should == true
      (@float_infinity < val).should == false
      (val < @float_infinity_neg).should == false
      (@float_infinity_neg < val).should == true
    }
  end

  it "properly handles NaN values" do
    @values += [@infinity, @infinity_neg, @nan]
    @values.each { |val|
      (@nan < val).should == false
      (val < @nan).should == false
    }
  end

  it "raises an ArgumentError if the argument can't be coerced into a BigDecimal" do
    -> {@zero         < nil }.should raise_error(ArgumentError)
    -> {@infinity     < nil }.should raise_error(ArgumentError)
    -> {@infinity_neg < nil }.should raise_error(ArgumentError)
    -> {@mixed        < nil }.should raise_error(ArgumentError)
    -> {@pos_int      < nil }.should raise_error(ArgumentError)
    -> {@neg_frac     < nil }.should raise_error(ArgumentError)
  end
end