minor: docs

lib/mongo/gridfs/grid_io.rb

@@ -168,7 +168,7 @@ module Mongo
       (@file_length / @chunk_size).to_i
     end
 
-    # An optimized read method for reading the whole file.
+    # Read a file in its entirety (optimized).
     def read_all
       buf = ''
       while true
@@ -179,6 +179,7 @@ module Mongo
       buf
     end
 
+    # Read a file incrementally.
     def read_length(length)
       cache_chunk_data
       remaining  = (@file_length - @file_position)

test/test_grid.rb

@@ -50,6 +50,9 @@ class GridTest < Test::Unit::TestCase
     file = @grid.get(id)
     io.rewind
     data = io.read
+    if data.respond_to?(:force_encoding)
+      data.force_encoding(:binary)
+    end
     read_data = ""
     while(chunk = file.read(read_length))
       read_data << chunk