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require_relative '../../spec_helper'
require_relative 'shared/modulo'
require 'bigdecimal'
module DivmodSpecs
def self.check_both_nan(array)
array.length.should == 2
array[0].nan?.should == true
array[1].nan?.should == true
end
def self.check_both_bigdecimal(array)
array.length.should == 2
array[0].kind_of?(BigDecimal).should == true
array[1].kind_of?(BigDecimal).should == true
end
end
# TODO: figure out a way to do the shared specs with helpers instead
# of spec'ing a method that does not really exist
describe "BigDecimal#mod_part_of_divmod" do
# BigDecimal#divmod[1] behaves exactly like #modulo
before :all do
class BigDecimal
def mod_part_of_divmod(arg)
divmod(arg)[1]
end
end
end
after :all do
class BigDecimal
undef mod_part_of_divmod
end
end
it_behaves_like :bigdecimal_modulo, :mod_part_of_divmod
it "raises ZeroDivisionError if other is zero" do
bd5667 = BigDecimal("5667.19")
lambda { bd5667.mod_part_of_divmod(0) }.should raise_error(ZeroDivisionError)
lambda { bd5667.mod_part_of_divmod(BigDecimal("0")) }.should raise_error(ZeroDivisionError)
lambda { @zero.mod_part_of_divmod(@zero) }.should raise_error(ZeroDivisionError)
end
end
describe "BigDecimal#divmod" do
before :each do
@a = BigDecimal("42.00000000000000000001")
@zero = BigDecimal("0")
@zero_pos = BigDecimal("+0")
@zero_neg = BigDecimal("-0")
@one = BigDecimal("1")
@mixed = BigDecimal("1.23456789")
@pos_int = BigDecimal("2E5555")
@neg_int = BigDecimal("-2E5555")
@pos_frac = BigDecimal("2E-9999")
@neg_frac = BigDecimal("-2E-9999")
@nan = BigDecimal("NaN")
@infinity = BigDecimal("Infinity")
@infinity_minus = BigDecimal("-Infinity")
@one_minus = BigDecimal("-1")
@frac_1 = BigDecimal("1E-99999")
@frac_2 = BigDecimal("0.9E-99999")
@special_vals = [@infinity, @infinity_minus, @nan]
@regular_vals = [
@one, @mixed, @pos_int, @neg_int, @pos_frac,
@neg_frac, @one_minus, @frac_1, @frac_2]
@zeroes = [@zero, @zero_pos, @zero_neg]
end
it "divides value, returns an array" do
res = @a.divmod(5)
res.kind_of?(Array).should == true
end
it "array contains quotient and modulus as BigDecimal" do
res = @a.divmod(5)
DivmodSpecs.check_both_bigdecimal(res)
res[0].should == BigDecimal('0.8E1')
res[1].should == BigDecimal('2.00000000000000000001')
BigDecimal('1').divmod(BigDecimal('2')).should == [0, 1]
BigDecimal('2').divmod(BigDecimal('1')).should == [2, 0]
BigDecimal('1').divmod(BigDecimal('-2')).should == [-1, -1]
BigDecimal('2').divmod(BigDecimal('-1')).should == [-2, 0]
BigDecimal('-1').divmod(BigDecimal('2')).should == [-1, 1]
BigDecimal('-2').divmod(BigDecimal('1')).should == [-2, 0]
end
it "can be reversed with * and +" do
# Example taken from BigDecimal documentation
a = BigDecimal("42")
b = BigDecimal("9")
q, m = a.divmod(b)
c = q * b + m
a.should == c
values = [@one, @one_minus, BigDecimal('2'), BigDecimal('-2'),
BigDecimal('5'), BigDecimal('-5'), BigDecimal('10'), BigDecimal('-10'),
BigDecimal('20'), BigDecimal('-20'), BigDecimal('100'), BigDecimal('-100'),
BigDecimal('1.23456789E10'), BigDecimal('-1.23456789E10')
]
# TODO: file MRI bug:
# BigDecimal('1').divmod(BigDecimal('3E-9'))[0] #=> 0.3E9,
# but really should be 0.333333333E9
values << BigDecimal('1E-10')
values << BigDecimal('-1E-10')
values << BigDecimal('2E55')
values << BigDecimal('-2E55')
values << BigDecimal('2E-5555')
values << BigDecimal('-2E-5555')
values_and_zeroes = values + @zeroes
values_and_zeroes.each do |val1|
values.each do |val2|
res = val1.divmod(val2)
DivmodSpecs.check_both_bigdecimal(res)
res[0].should == ((val1/val2).floor)
res[1].should == (val1 - res[0] * val2)
end
end
end
it "returns an array of two NaNs if NaN is involved" do
(@special_vals + @regular_vals + @zeroes).each do |val|
DivmodSpecs.check_both_nan(val.divmod(@nan))
DivmodSpecs.check_both_nan(@nan.divmod(val))
end
end
it "raises ZeroDivisionError if the divisor is zero" do
(@special_vals + @regular_vals + @zeroes - [@nan]).each do |val|
@zeroes.each do |zero|
lambda { val.divmod(zero) }.should raise_error(ZeroDivisionError)
end
end
end
it "returns an array of Infinity and NaN if the dividend is Infinity" do
@regular_vals.each do |val|
array = @infinity.divmod(val)
array.length.should == 2
array[0].infinite?.should == (val > 0 ? 1 : -1)
array[1].nan?.should == true
end
end
it "returns an array of zero and the dividend if the divisor is Infinity" do
@regular_vals.each do |val|
array = val.divmod(@infinity)
array.length.should == 2
array[0].should == @zero
array[1].should == val
end
end
it "returns an array of two zero if the diviend is zero" do
@zeroes.each do |zero|
@regular_vals.each do |val|
zero.divmod(val).should == [@zero, @zero]
end
end
end
it "raises TypeError if the argument cannot be coerced to BigDecimal" do
lambda {
@one.divmod('1')
}.should raise_error(TypeError)
end
end
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