require File.expand_path('../../../spec_helper', __FILE__) require File.expand_path('../fixtures/classes', __FILE__) describe "IO#sysread on a file" do before :each do @file_name = tmp("IO_sysread_file") + $$.to_s File.open(@file_name, "w") do |f| # write some stuff f.write("012345678901234567890123456789") end @file = File.open(@file_name, "r+") end after :each do @file.close rm_r @file_name end it "reads the specified number of bytes from the file" do @file.sysread(15).should == "012345678901234" end it "reads the specified number of bytes from the file to the buffer" do buf = "" # empty buffer @file.sysread(15, buf).should == buf buf.should == "012345678901234" @file.rewind buf = "ABCDE" # small buffer @file.sysread(15, buf).should == buf buf.should == "012345678901234" @file.rewind buf = "ABCDE" * 5 # large buffer @file.sysread(15, buf).should == buf buf.should == "012345678901234" end it "coerces the second argument to string and uses it as a buffer" do buf = "ABCDE" (obj = mock("buff")).should_receive(:to_str).any_number_of_times.and_return(buf) @file.sysread(15, obj).should == buf buf.should == "012345678901234" end it "advances the position of the file by the specified number of bytes" do @file.sysread(15) @file.sysread(5).should == "56789" end it "reads normally even when called immediately after a buffered IO#read" do @file.read(15) @file.sysread(5).should == "56789" end it "does not raise error if called after IO#read followed by IO#write" do @file.read(5) @file.write("abcde") lambda { @file.sysread(5) }.should_not raise_error(IOError) end it "does not raise error if called after IO#read followed by IO#syswrite" do @file.read(5) @file.syswrite("abcde") lambda { @file.sysread(5) }.should_not raise_error(IOError) end it "reads updated content after the flushed buffered IO#write" do @file.write("abcde") @file.flush @file.sysread(5).should == "56789" File.open(@file_name) do |f| f.sysread(10).should == "abcde56789" end end it "raises IOError on closed stream" do lambda { IOSpecs.closed_io.sysread(5) }.should raise_error(IOError) end end describe "IO#sysread" do before do @read, @write = IO.pipe end after do @read.close @write.close end it "returns a smaller string if less than size bytes are available" do @write.syswrite "ab" @read.sysread(3).should == "ab" end end