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# -*- encoding: utf-8 -*-
require File.expand_path('../../../spec_helper', __FILE__)
require File.expand_path('../fixtures/classes', __FILE__)
describe "IO#ungetc" do
before :each do
@io = IOSpecs.io_fixture "lines.txt"
@empty = tmp('empty.txt')
end
after :each do
@io.close unless @io.closed?
rm_r @empty
end
it "pushes back one character onto stream" do
@io.getc.should == ?V
@io.ungetc(86)
@io.getc.should == ?V
@io.ungetc(10)
@io.getc.should == ?\n
@io.getc.should == ?o
@io.getc.should == ?i
# read the rest of line
@io.readline.should == "ci la ligne une.\n"
@io.getc.should == ?Q
@io.ungetc(99)
@io.getc.should == ?c
end
it "pushes back one character when invoked at the end of the stream" do
# read entire content
@io.read
@io.ungetc(100)
@io.getc.should == ?d
end
it "pushes back one character when invoked at the start of the stream" do
@io.read(0)
@io.ungetc(100)
@io.getc.should == ?d
end
it "pushes back one character when invoked on empty stream" do
touch(@empty)
File.open(@empty) { |empty|
empty.getc().should == nil
empty.ungetc(10)
empty.getc.should == ?\n
}
end
it "affects EOF state" do
touch(@empty)
File.open(@empty) { |empty|
empty.eof?.should == true
empty.getc.should == nil
empty.ungetc(100)
empty.eof?.should == false
}
end
it "adjusts the stream position" do
@io.pos.should == 0
# read one char
c = @io.getc
@io.pos.should == 1
@io.ungetc(c)
@io.pos.should == 0
# read all
@io.read
pos = @io.pos
@io.ungetc(98)
@io.pos.should == pos - 1
end
# TODO: file MRI bug
# Another specified behavior that MRI doesn't follow:
# "Has no effect with unbuffered reads (such as IO#sysread)."
#
#it "has no effect with unbuffered reads" do
# length = File.size(@io_name)
# content = @io.sysread(length)
# @io.rewind
# @io.ungetc(100)
# @io.sysread(length).should == content
#end
it "makes subsequent unbuffered operations to raise IOError" do
@io.getc
@io.ungetc(100)
lambda { @io.sysread(1) }.should raise_error(IOError)
end
ruby_version_is "" ... "1.9" do
it "raises IOError when invoked on stream that was not yet read" do
lambda { @io.ungetc(100) }.should raise_error(IOError)
end
end
ruby_version_is "1.9" do
it "does not affect the stream and returns nil when passed nil" do
@io.getc.should == ?V
@io.ungetc(nil)
@io.getc.should == ?o
end
it "puts one or more characters back in the stream" do
@io.gets
@io.ungetc("Aquí ").should be_nil
@io.gets.chomp.should == "Aquí Qui è la linea due."
end
it "calls #to_str to convert the argument if it is not an Integer" do
chars = mock("io ungetc")
chars.should_receive(:to_str).and_return("Aquí ")
@io.ungetc(chars).should be_nil
@io.gets.chomp.should == "Aquí Voici la ligne une."
end
it "returns nil when invoked on stream that was not yet read" do
@io.ungetc(100).should be_nil
end
end
it "raises IOError on closed stream" do
@io.getc
@io.close
lambda { @io.ungetc(100) }.should raise_error(IOError)
end
end
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