require_relative '../../spec_helper' require 'strscan' describe "StringScanner#unscan" do before :each do @s = StringScanner.new("This is a test") end it "set the scan pointer to the previous position" do @s.scan(/This/) @s.unscan @s.matched.should == nil @s.pos.should == 0 end it "remember only one previous position" do @s.scan(/This/) pos = @s.pos @s.scan(/ is/) @s.unscan @s.pos.should == pos end it "raises a ScanError when the previous match had failed" do -> { @s.unscan }.should raise_error(ScanError) -> { @s.scan(/\d/); @s.unscan }.should raise_error(ScanError) end end