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author | Benoit Daloze <eregontp@gmail.com> | 2020-01-28 20:47:48 +0100 |
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committer | Benoit Daloze <eregontp@gmail.com> | 2020-01-28 20:47:48 +0100 |
commit | 809f0b8a1357f14f9645210d4812f4400c8d397e (patch) | |
tree | 7ce6192f94b1dc4b004798aa5d0c4d6bac02577f /spec/ruby/core/integer/element_reference_spec.rb | |
parent | ed377cc9aaf1ccbede19ddc6c464f5fbf3cabc34 (diff) | |
download | ruby-809f0b8a1357f14f9645210d4812f4400c8d397e.tar.gz |
Update to ruby/spec@f8a2d54
Diffstat (limited to 'spec/ruby/core/integer/element_reference_spec.rb')
-rw-r--r-- | spec/ruby/core/integer/element_reference_spec.rb | 85 |
1 files changed, 85 insertions, 0 deletions
diff --git a/spec/ruby/core/integer/element_reference_spec.rb b/spec/ruby/core/integer/element_reference_spec.rb index 99283fac34..4c236a11e7 100644 --- a/spec/ruby/core/integer/element_reference_spec.rb +++ b/spec/ruby/core/integer/element_reference_spec.rb @@ -78,6 +78,91 @@ describe "Integer#[]" do it "returns 0 when passed a Float in the range of a Bignum" do 3[bignum_value.to_f].should == 0 end + + ruby_version_is "2.7" do + context "when index and length passed" do + it "returns specified number of bits from specified position" do + 0b101001101[2, 4].should == 0b0011 + 0b101001101[2, 5].should == 0b10011 + 0b101001101[2, 7].should == 0b1010011 + end + + it "ensures n[i, len] equals to (n >> i) & ((1 << len) - 1)" do + n = 0b101001101; i = 2; len = 4 + n[i, len].should == (n >> i) & ((1 << len) - 1) + end + + it "moves start position to the most significant bits when negative index passed" do + 0b000001[-1, 4].should == 0b10 + 0b000001[-2, 4].should == 0b100 + 0b000001[-3, 4].should == 0b1000 + end + + it "ignores negative length" do + 0b101001101[1, -1].should == 0b10100110 + 0b101001101[2, -1].should == 0b1010011 + 0b101001101[3, -1].should == 0b101001 + + 0b101001101[3, -5].should == 0b101001 + 0b101001101[3, -15].should == 0b101001 + 0b101001101[3, -125].should == 0b101001 + end + end + + context "when range passed" do + it "returns bits specified by range" do + 0b101001101[2..5].should == 0b0011 + 0b101001101[2..6].should == 0b10011 + 0b101001101[2..8].should == 0b1010011 + end + + it "ensures n[i..j] equals to (n >> i) & ((1 << (j - i + 1)) - 1)" do + n = 0b101001101; i = 2; j = 5 + n[i..j].should == (n >> i) & ((1 << (j - i + 1)) - 1) + end + + it "ensures n[i..] equals to (n >> i)" do + eval("0b101001101[3..]").should == 0b101001101 >> 3 + end + + it "moves lower boundary to the most significant bits when negative value passed" do + 0b000001[-1, 4].should == 0b10 + 0b000001[-2, 4].should == 0b100 + 0b000001[-3, 4].should == 0b1000 + end + + it "ignores negative upper boundary" do + 0b101001101[1..-1].should == 0b10100110 + 0b101001101[1..-2].should == 0b10100110 + 0b101001101[1..-3].should == 0b10100110 + end + + it "ignores upper boundary smaller than lower boundary" do + 0b101001101[4..1].should == 0b10100 + 0b101001101[4..2].should == 0b10100 + 0b101001101[4..3].should == 0b10100 + end + + it "raises FloatDomainError if any boundary is infinity" do + -> { 0x0001[3..Float::INFINITY] }.should raise_error(FloatDomainError, /Infinity/) + -> { 0x0001[-Float::INFINITY..3] }.should raise_error(FloatDomainError, /-Infinity/) + end + + context "when passed (..i)" do + it "returns 0 if all i bits equal 0" do + eval("0b10000[..1]").should == 0 + eval("0b10000[..2]").should == 0 + eval("0b10000[..3]").should == 0 + end + + it "raises ArgumentError if any of i bit equals 1" do + -> { + eval("0b111110[..3]") + }.should raise_error(ArgumentError, /The beginless range for Integer#\[\] results in infinity/) + end + end + end + end end context "bignum" do |