diff options
Diffstat (limited to 'spec/ruby/core/bignum/left_shift_spec.rb')
-rw-r--r-- | spec/ruby/core/bignum/left_shift_spec.rb | 73 |
1 files changed, 73 insertions, 0 deletions
diff --git a/spec/ruby/core/bignum/left_shift_spec.rb b/spec/ruby/core/bignum/left_shift_spec.rb new file mode 100644 index 0000000000..364f51b708 --- /dev/null +++ b/spec/ruby/core/bignum/left_shift_spec.rb @@ -0,0 +1,73 @@ +require File.expand_path('../../../spec_helper', __FILE__) + +describe "Bignum#<< with n << m" do + before :each do + @bignum = bignum_value * 16 + end + + it "returns n shifted left m bits when n > 0, m > 0" do + (@bignum << 4).should == 2361183241434822606848 + end + + it "returns n shifted left m bits when n < 0, m > 0" do + (-@bignum << 9).should == -75557863725914323419136 + end + + it "returns n shifted right m bits when n > 0, m < 0" do + (@bignum << -1).should == 73786976294838206464 + end + + it "returns n shifted right m bits when n < 0, m < 0" do + (-@bignum << -2).should == -36893488147419103232 + end + + it "returns n when n > 0, m == 0" do + (@bignum << 0).should == @bignum + end + + it "returns n when n < 0, m == 0" do + (-@bignum << 0).should == -@bignum + end + + it "returns 0 when m < 0 and m == p where 2**p > n >= 2**(p-1)" do + (@bignum << -68).should == 0 + end + + it "returns 0 when m < 0 and m is a Bignum" do + (@bignum << -bignum_value).should == 0 + end + + it "returns a Fixnum == fixnum_max when (fixnum_max * 2) << -1 and n > 0" do + result = (fixnum_max * 2) << -1 + result.should be_an_instance_of(Fixnum) + result.should == fixnum_max + end + + it "returns a Fixnum == fixnum_min when (fixnum_min * 2) << -1 and n < 0" do + result = (fixnum_min * 2) << -1 + result.should be_an_instance_of(Fixnum) + result.should == fixnum_min + end + + it "calls #to_int to convert the argument to an Integer" do + obj = mock("4") + obj.should_receive(:to_int).and_return(4) + + (@bignum << obj).should == 2361183241434822606848 + end + + it "raises a TypeError when #to_int does not return an Integer" do + obj = mock("a string") + obj.should_receive(:to_int).and_return("asdf") + + lambda { @bignum << obj }.should raise_error(TypeError) + end + + it "raises a TypeError when passed nil" do + lambda { @bignum << nil }.should raise_error(TypeError) + end + + it "raises a TypeError when passed a String" do + lambda { @bignum << "4" }.should raise_error(TypeError) + end +end |