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path: root/spec/ruby/library/bigdecimal/remainder_spec.rb
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require_relative '../../spec_helper'

ruby_version_is ""..."3.4" do
  require 'bigdecimal'

  describe "BigDecimal#remainder" do

    before :each do
      @zero = BigDecimal("0")
      @one = BigDecimal("1")
      @three = BigDecimal("3")
      @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")
    end

    it "it equals modulo, if both values are of same sign" do
      BigDecimal('1234567890123456789012345679').remainder(BigDecimal('1')).should == @zero
      BigDecimal('123456789').remainder(BigDecimal('333333333333333333333333333E-50')).should == BigDecimal('0.12233333333333333333345679E-24')

      @mixed.remainder(@pos_frac).should == @mixed % @pos_frac
      @pos_int.remainder(@pos_frac).should == @pos_int % @pos_frac
      @neg_frac.remainder(@neg_int).should == @neg_frac % @neg_int
      @neg_int.remainder(@neg_frac).should == @neg_int % @neg_frac
    end

    it "means self-arg*(self/arg).truncate" do
      @mixed.remainder(@neg_frac).should == @mixed - @neg_frac * (@mixed / @neg_frac).truncate
      @pos_int.remainder(@neg_frac).should == @pos_int - @neg_frac * (@pos_int / @neg_frac).truncate
      @neg_frac.remainder(@pos_int).should == @neg_frac - @pos_int * (@neg_frac / @pos_int).truncate
      @neg_int.remainder(@pos_frac).should == @neg_int - @pos_frac * (@neg_int / @pos_frac).truncate
    end

    it "returns NaN used with zero" do
      @mixed.remainder(@zero).should.nan?
      @zero.remainder(@zero).should.nan?
    end

    it "returns zero if used on zero" do
      @zero.remainder(@mixed).should == @zero
    end

    it "returns NaN if NaN is involved" do
      @nan.remainder(@nan).should.nan?
      @nan.remainder(@one).should.nan?
      @one.remainder(@nan).should.nan?
      @infinity.remainder(@nan).should.nan?
      @nan.remainder(@infinity).should.nan?
    end

    version_is BigDecimal::VERSION, ""..."3.1.4" do #ruby_version_is ""..."3.3" do
      it "returns NaN if Infinity is involved" do
        @infinity.remainder(@infinity).should.nan?
        @infinity.remainder(@one).should.nan?
        @infinity.remainder(@mixed).should.nan?
        @infinity.remainder(@one_minus).should.nan?
        @infinity.remainder(@frac_1).should.nan?
        @one.remainder(@infinity).should.nan?

        @infinity_minus.remainder(@infinity_minus).should.nan?
        @infinity_minus.remainder(@one).should.nan?
        @one.remainder(@infinity_minus).should.nan?
        @frac_2.remainder(@infinity_minus).should.nan?

        @infinity.remainder(@infinity_minus).should.nan?
        @infinity_minus.remainder(@infinity).should.nan?
      end
    end

    it "coerces arguments to BigDecimal if possible" do
      @three.remainder(2).should == @one
    end

    describe "with Object" do
      it "tries to coerce the other operand to self" do
        object = mock("Object")
        object.should_receive(:coerce).with(@three).and_return([@three, 2])
        @three.remainder(object).should == @one
      end
    end

    it "raises TypeError if the argument cannot be coerced to BigDecimal" do
      -> {
        @one.remainder('2')
      }.should raise_error(TypeError)
    end

  end
end