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Diffstat (limited to 'spec/rubyspec/shared/rational/exponent.rb')
| -rw-r--r-- | spec/rubyspec/shared/rational/exponent.rb | 176 |
1 files changed, 176 insertions, 0 deletions
diff --git a/spec/rubyspec/shared/rational/exponent.rb b/spec/rubyspec/shared/rational/exponent.rb new file mode 100644 index 0000000000..7e7c5be7c1 --- /dev/null +++ b/spec/rubyspec/shared/rational/exponent.rb @@ -0,0 +1,176 @@ +require File.expand_path('../../../spec_helper', __FILE__) + +describe :rational_exponent, shared: true do + describe "when passed Rational" do + conflicts_with :Prime do + it "returns Rational(1) if the exponent is Rational(0)" do + (Rational(0) ** Rational(0)).should eql(Rational(1)) + (Rational(1) ** Rational(0)).should eql(Rational(1)) + (Rational(3, 4) ** Rational(0)).should eql(Rational(1)) + (Rational(-1) ** Rational(0)).should eql(Rational(1)) + (Rational(-3, 4) ** Rational(0)).should eql(Rational(1)) + (Rational(bignum_value) ** Rational(0)).should eql(Rational(1)) + (Rational(-bignum_value) ** Rational(0)).should eql(Rational(1)) + end + + it "returns self raised to the argument as a Rational if the exponent's denominator is 1" do + (Rational(3, 4) ** Rational(1, 1)).should eql(Rational(3, 4)) + (Rational(3, 4) ** Rational(2, 1)).should eql(Rational(9, 16)) + (Rational(3, 4) ** Rational(-1, 1)).should eql(Rational(4, 3)) + (Rational(3, 4) ** Rational(-2, 1)).should eql(Rational(16, 9)) + end + + it "returns self raised to the argument as a Float if the exponent's denominator is not 1" do + (Rational(3, 4) ** Rational(4, 3)).should be_close(0.681420222312052, TOLERANCE) + (Rational(3, 4) ** Rational(-4, 3)).should be_close(1.46752322173095, TOLERANCE) + (Rational(3, 4) ** Rational(4, -3)).should be_close(1.46752322173095, TOLERANCE) + end + + it "returns a complex number when self is negative and the passed argument is not 0" do + (Rational(-3, 4) ** Rational(-4, 3)).should be_close(Complex(-0.7337616108654732, 1.2709123906625817), TOLERANCE) + end + end + end + + describe "when passed Integer" do + it "returns the Rational value of self raised to the passed argument" do + (Rational(3, 4) ** 4).should == Rational(81, 256) + (Rational(3, 4) ** -4).should == Rational(256, 81) + (Rational(-3, 4) ** -4).should == Rational(256, 81) + (Rational(3, -4) ** -4).should == Rational(256, 81) + + (Rational(bignum_value, 4) ** 4).should == Rational(28269553036454149273332760011886696253239742350009903329945699220681916416, 1) + (Rational(3, bignum_value) ** -4).should == Rational(7237005577332262213973186563042994240829374041602535252466099000494570602496, 81) + (Rational(-bignum_value, 4) ** -4).should == Rational(1, 28269553036454149273332760011886696253239742350009903329945699220681916416) + (Rational(3, -bignum_value) ** -4).should == Rational(7237005577332262213973186563042994240829374041602535252466099000494570602496, 81) + end + + conflicts_with :Prime do + it "returns Rational(1, 1) when the passed argument is 0" do + (Rational(3, 4) ** 0).should eql(Rational(1, 1)) + (Rational(-3, 4) ** 0).should eql(Rational(1, 1)) + (Rational(3, -4) ** 0).should eql(Rational(1, 1)) + + (Rational(bignum_value, 4) ** 0).should eql(Rational(1, 1)) + (Rational(3, -bignum_value) ** 0).should eql(Rational(1, 1)) + end + end + end + + describe "when passed Bignum" do + # #5713 + it "returns Rational(0) when self is Rational(0) and the exponent is positive" do + (Rational(0) ** bignum_value).should eql(Rational(0)) + end + + it "raises ZeroDivisionError when self is Rational(0) and the exponent is negative" do + lambda { Rational(0) ** -bignum_value }.should raise_error(ZeroDivisionError) + end + + it "returns Rational(1) when self is Rational(1)" do + (Rational(1) ** bignum_value).should eql(Rational(1)) + (Rational(1) ** -bignum_value).should eql(Rational(1)) + end + + it "returns Rational(1) when self is Rational(-1) and the exponent is positive and even" do + (Rational(-1) ** bignum_value(0)).should eql(Rational(1)) + (Rational(-1) ** bignum_value(2)).should eql(Rational(1)) + end + + it "returns Rational(-1) when self is Rational(-1) and the exponent is positive and odd" do + (Rational(-1) ** bignum_value(1)).should eql(Rational(-1)) + (Rational(-1) ** bignum_value(3)).should eql(Rational(-1)) + end + + it "returns positive Infinity when self is > 1" do + (Rational(2) ** bignum_value).infinite?.should == 1 + (Rational(fixnum_max) ** bignum_value).infinite?.should == 1 + end + + it "returns 0.0 when self is > 1 and the exponent is negative" do + (Rational(2) ** -bignum_value).should eql(0.0) + (Rational(fixnum_max) ** -bignum_value).should eql(0.0) + end + + # Fails on linux due to pow() bugs in glibc: http://sources.redhat.com/bugzilla/show_bug.cgi?id=3866 + platform_is_not :linux do + it "returns positive Infinity when self < -1" do + (Rational(-2) ** bignum_value).infinite?.should == 1 + (Rational(-2) ** (bignum_value + 1)).infinite?.should == 1 + (Rational(fixnum_min) ** bignum_value).infinite?.should == 1 + end + + it "returns 0.0 when self is < -1 and the exponent is negative" do + (Rational(-2) ** -bignum_value).should eql(0.0) + (Rational(fixnum_min) ** -bignum_value).should eql(0.0) + end + end + end + + describe "when passed Float" do + it "returns self converted to Float and raised to the passed argument" do + (Rational(3, 1) ** 3.0).should eql(27.0) + (Rational(3, 1) ** 1.5).should be_close(5.19615242270663, TOLERANCE) + (Rational(3, 1) ** -1.5).should be_close(0.192450089729875, TOLERANCE) + end + + it "returns a complex number if self is negative and the passed argument is not 0" do + (Rational(-3, 2) ** 1.5).should be_close(Complex(-3.374618290464398e-16, -1.8371173070873836), TOLERANCE) + (Rational(3, -2) ** 1.5).should be_close(Complex(-3.374618290464398e-16, -1.8371173070873836), TOLERANCE) + (Rational(3, -2) ** -1.5).should be_close(Complex(-9.998869008783402e-17, 0.5443310539518174), TOLERANCE) + end + + it "returns Complex(1.0) when the passed argument is 0.0" do + (Rational(3, 4) ** 0.0).should == Complex(1.0) + (Rational(-3, 4) ** 0.0).should == Complex(1.0) + (Rational(-3, 4) ** 0.0).should == Complex(1.0) + end + end + + it "calls #coerce on the passed argument with self" do + rational = Rational(3, 4) + obj = mock("Object") + obj.should_receive(:coerce).with(rational).and_return([1, 2]) + + rational ** obj + end + + it "calls #** on the coerced Rational with the coerced Object" do + rational = Rational(3, 4) + + coerced_rational = mock("Coerced Rational") + coerced_rational.should_receive(:**).and_return(:result) + + coerced_obj = mock("Coerced Object") + + obj = mock("Object") + obj.should_receive(:coerce).and_return([coerced_rational, coerced_obj]) + + (rational ** obj).should == :result + end + + it "raises ZeroDivisionError for Rational(0, 1) passed a negative Integer" do + [-1, -4, -9999].each do |exponent| + lambda { Rational(0, 1) ** exponent }.should raise_error(ZeroDivisionError, "divided by 0") + end + end + + it "raises ZeroDivisionError for Rational(0, 1) passed a negative Rational with denominator 1" do + [Rational(-1, 1), Rational(-3, 1)].each do |exponent| + lambda { Rational(0, 1) ** exponent }.should raise_error(ZeroDivisionError, "divided by 0") + end + end + + # #7513 + it "raises ZeroDivisionError for Rational(0, 1) passed a negative Rational" do + lambda { Rational(0, 1) ** Rational(-3, 2) }.should raise_error(ZeroDivisionError, "divided by 0") + end + + platform_is_not :solaris do # See https://github.com/ruby/spec/issues/134 + it "returns Infinity for Rational(0, 1) passed a negative Float" do + [-1.0, -3.0, -3.14].each do |exponent| + (Rational(0, 1) ** exponent).infinite?.should == 1 + end + end + end +end |