Make NullIO#read mimic IO#read

lib/puma/null_io.rb

@@ -4,7 +4,6 @@ module Puma
   # Used as the value for rack.input when the request has no body.
   #
   class NullIO
-
     # Always returns nil
     #
     def gets
@@ -16,10 +15,10 @@ def gets
     def each
     end
 
-    # Always returns nil
+    # Mimics IO#read with no data
     #
-    def read(count)
-      nil
+    def read(count=nil,buffer=nil)
+      (count && count > 0) ? nil : ""
     end
 
     # Does nothing

test/test_null_io.rb

@@ -0,0 +1,31 @@
+require 'puma/null_io'
+require 'test/unit'
+
+class TestNullIO < Test::Unit::TestCase
+  attr_accessor :nio
+  def setup
+    self.nio = Puma::NullIO.new
+  end
+
+  def test_read_with_no_arguments
+    assert_equal "", nio.read
+  end
+
+  def test_read_with_nil_length
+    assert_equal "", nio.read(nil)
+  end
+
+  def test_read_with_zero_length
+    assert_equal "", nio.read(0)
+  end
+
+  def test_read_with_positive_integer_length
+    assert_nil nio.read(1)
+  end
+
+  def test_read_with_length_and_buffer
+    buf = ""
+    assert_nil nio.read(1,buf)
+    assert_equal "", buf
+  end
+end