diff options
Diffstat (limited to 'spec/ruby/core/fixnum/bit_length_spec.rb')
| -rw-r--r-- | spec/ruby/core/fixnum/bit_length_spec.rb | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/spec/ruby/core/fixnum/bit_length_spec.rb b/spec/ruby/core/fixnum/bit_length_spec.rb new file mode 100644 index 0000000000..8c9f69b7d7 --- /dev/null +++ b/spec/ruby/core/fixnum/bit_length_spec.rb @@ -0,0 +1,42 @@ +require File.expand_path('../../../spec_helper', __FILE__) + +describe "Fixnum#bit_length" do + it "returns the position of the leftmost bit of a positive number" do + 0.bit_length.should == 0 + 1.bit_length.should == 1 + 2.bit_length.should == 2 + 3.bit_length.should == 2 + 4.bit_length.should == 3 + n = fixnum_max.bit_length + fixnum_max[n].should == 0 + fixnum_max[n-1].should == 1 + + 0.bit_length.should == 0 + 1.bit_length.should == 1 + 0xff.bit_length.should == 8 + 0x100.bit_length.should == 9 + (2**12-1).bit_length.should == 12 + (2**12).bit_length.should == 13 + (2**12+1).bit_length.should == 13 + end + + it "returns the position of the leftmost 0 bit of a negative number" do + -1.bit_length.should == 0 + -2.bit_length.should == 1 + -3.bit_length.should == 2 + -4.bit_length.should == 2 + -5.bit_length.should == 3 + n = fixnum_min.bit_length + fixnum_min[n].should == 1 + fixnum_min[n-1].should == 0 + + (-2**12-1).bit_length.should == 13 + (-2**12).bit_length.should == 12 + (-2**12+1).bit_length.should == 12 + -0x101.bit_length.should == 9 + -0x100.bit_length.should == 8 + -0xff.bit_length.should == 8 + -2.bit_length.should == 1 + -1.bit_length.should == 0 + end +end |