require_relative '../../spec_helper' require "stringio" describe "StringIO#truncate when passed [length]" do before :each do @io = StringIO.new('123456789') end # TODO: Report to Ruby-Core: The RDoc says it always returns 0 it "returns the passed length" do @io.truncate(4).should eql(4) @io.truncate(10).should eql(10) end it "truncated the underlying string down to the passed length" do @io.truncate(4) @io.string.should == "1234" end it "does not create a copy of the underlying string" do io = StringIO.new(str = "123456789") io.truncate(4) io.string.should equal(str) end it "does not change the position" do @io.pos = 7 @io.truncate(4) @io.pos.should eql(7) end it "can grow a string to a larger size, padding it with \\000" do @io.truncate(12) @io.string.should == "123456789\000\000\000" end it "raises an Errno::EINVAL when the passed length is negative" do lambda { @io.truncate(-1) }.should raise_error(Errno::EINVAL) lambda { @io.truncate(-10) }.should raise_error(Errno::EINVAL) end it "tries to convert the passed length to an Integer using #to_int" do obj = mock("to_int") obj.should_receive(:to_int).and_return(4) @io.truncate(obj) @io.string.should == "1234" end it "returns the passed length Object, NOT the result of #to_int" do obj = mock("to_int") obj.should_receive(:to_int).and_return(4) @io.truncate(obj).should equal(obj) end it "raises a TypeError when the passed length can't be converted to an Integer" do lambda { @io.truncate(Object.new) }.should raise_error(TypeError) end end describe "StringIO#truncate when self is not writable" do it "raises an IOError" do io = StringIO.new("test", "r") lambda { io.truncate(2) }.should raise_error(IOError) io = StringIO.new("test") io.close_write lambda { io.truncate(2) }.should raise_error(IOError) end end