spec/ruby/library/stringscanner/shared/peek.rb


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describe :strscan_peek, shared: true do
  before :each do
    @s = StringScanner.new('This is a test')
  end

  it "returns at most the specified number of bytes from the current position" do
    @s.send(@method, 4).should == "This"
    @s.pos.should == 0
    @s.pos = 5
    @s.send(@method, 2).should == "is"
    @s.send(@method, 1000).should == "is a test"

    s = StringScanner.new("été")
    s.send(@method, 2).should == "é"
  end

  it "returns an empty string when the passed argument is zero" do
    @s.send(@method, 0).should == ""
  end

  it "raises a ArgumentError when the passed argument is negative" do
    -> { @s.send(@method, -2) }.should raise_error(ArgumentError)
  end

  it "raises a RangeError when the passed argument is a Bignum" do
    -> { @s.send(@method, bignum_value) }.should raise_error(RangeError)
  end

  it "returns an instance of String when passed a String subclass" do
    cls = Class.new(String)
    sub = cls.new("abc")

    s = StringScanner.new(sub)

    ch = s.send(@method, 1)
    ch.should_not be_kind_of(cls)
    ch.should be_an_instance_of(String)
  end

  it "taints the returned String if the input was tainted" do
    str = 'abc'
    str.taint

    s = StringScanner.new(str)
    s.send(@method, 1).tainted?.should be_true
  end
end