spec/ruby/library/bigdecimal/core_spec.rb

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

describe "Core extension by bigdecimal" do
  context "Integer#coerce" do
    it "produces Floats" do
      x, y = 3.coerce(BigDecimal("3.4"))
      x.class.should == Float
      x.should == 3.4
      y.class.should == Float
      y.should == 3.0
    end
  end

  describe "Time.at passed BigDecimal" do
    it "doesn't round input value" do
      Time.at(BigDecimal('1.1')).to_f.should == 1.1
    end
  end

  describe "BigDecimal#log" do
    it "handles high-precision Rational arguments" do
      result = BigDecimal('0.22314354220170971436137296411949880462556361100856391620766259404746040597133837784E0')
      r = Rational(1_234_567_890, 987_654_321)
      BigMath.log(r, 50).should == result
    end
  end

  describe "Rational#coerce" do
    it "returns the passed argument, self as Float, when given a Float" do
      result = Rational(3, 4).coerce(1.0)
      result.should == [1.0, 0.75]
      result.first.is_a?(Float).should be_true
      result.last.is_a?(Float).should be_true
    end

    it "returns the passed argument, self as Rational, when given an Integer" do
      result = Rational(3, 4).coerce(10)
      result.should == [Rational(10, 1), Rational(3, 4)]
      result.first.is_a?(Rational).should be_true
      result.last.is_a?(Rational).should be_true
    end

    it "coerces to Rational, when given a Complex" do
      Rational(3, 4).coerce(Complex(5)).should == [Rational(5, 1), Rational(3, 4)]
      Rational(12, 4).coerce(Complex(5, 1)).should == [Complex(5, 1), Complex(3)]
    end

    it "returns [argument, self] when given a Rational" do
      Rational(3, 7).coerce(Rational(9, 2)).should == [Rational(9, 2), Rational(3, 7)]
    end

    it "raises an error when passed a BigDecimal" do
      -> {
        Rational(500, 3).coerce(BigDecimal('166.666666666'))
      }.should raise_error(TypeError, /BigDecimal can't be coerced into Rational/)
    end
  end
end