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-rw-r--r--spec/ruby/core/bignum/left_shift_spec.rb73
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
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+++ 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