Fix tests for 1.9.2

lib/zip/inflater.rb

@@ -7,9 +7,9 @@ module Zip
       @has_returned_empty_string = false
     end
 
-    def sysread(number_of_bytes = nil, buf = nil)
+    def sysread(number_of_bytes = nil, buf = '')
       readEverything = number_of_bytes.nil?
-      while (readEverything || @output_buffer.bytesize < number_of_bytes)
+      while readEverything || @output_buffer.bytesize < number_of_bytes
         break if internal_input_finished?
         @output_buffer << internal_produce_input(buf)
       end
@@ -37,7 +37,7 @@ module Zip
 
     private
 
-    def internal_produce_input(buf = nil)
+    def internal_produce_input(buf = '')
       retried = 0
       begin
         @zlib_inflater.inflate(@input_stream.read(Decompressor::CHUNK_SIZE, buf))

lib/zip/ioextras/abstract_input_stream.rb

@@ -17,7 +17,7 @@ module Zip
       attr_accessor :lineno
       attr_reader :pos
 
-      def read(number_of_bytes = nil, buf = nil)
+      def read(number_of_bytes = nil, buf = '')
         tbuf = if @output_buffer.bytesize > 0
                  if number_of_bytes <= @output_buffer.bytesize
                    @output_buffer.slice!(0, number_of_bytes)

lib/zip/pass_thru_decompressor.rb

@@ -8,7 +8,7 @@ module Zip
       @has_returned_empty_string = false
     end
 
-    def sysread(number_of_bytes = nil, buf = nil)
+    def sysread(number_of_bytes = nil, buf = '')
       if input_finished?
         has_returned_empty_string_val = @has_returned_empty_string
         @has_returned_empty_string = true
@@ -16,7 +16,7 @@ module Zip
         return
       end
 
-      if (number_of_bytes == nil || @read_so_far + number_of_bytes > @chars_to_read)
+      if number_of_bytes.nil? || @read_so_far + number_of_bytes > @chars_to_read
         number_of_bytes = @chars_to_read - @read_so_far
       end
       @read_so_far += number_of_bytes

test/ziptest.rb

@@ -8,6 +8,7 @@ $: << "../lib"
 require 'test/unit'
 require 'fileutils'
 require 'zip'
+require 'stringio'
 require 'gentestfiles'
 
 class ZipEntryTest < Test::Unit::TestCase