This patch to webob.byterange fixes "Range: bytes=-17" for Content-Length < 17 (eg. 10 in my tests).

NewFunctionalTest.diff

diff --git a/test/functional/tests.py b/test/functional/tests.py
index dd589e6..cd734ac 100644
--- a/test/functional/tests.py
+++ b/test/functional/tests.py
@@ -1147,6 +1147,13 @@ class TestFile(Base):
         hdrs = {'Range': '0-4'}
         self.assert_(file.read(hdrs=hdrs) == data, range_string)
 
+        # "If the entity is shorter than the specified suffix-length, the
+        # entire entity-body is used."
+        range_string = 'bytes=-%d' % (file_length + 10)
+        hdrs = {'Range': range_string}
+        self.assert_(file.read(hdrs=hdrs) == data, range_string)
+
+
     def testRangedGetsWithLWSinHeader(self):
         #Skip this test until webob 1.2 can tolerate LWS in Range header.
         from webob.byterange import Range

WebobFix.diff

swiftstack@saio:~/swift/swift/obj$ diff -u /usr/share/pyshared/webob/byterange.py.orig /usr/share/pyshared/webob/byterange.py
--- /usr/share/pyshared/webob/byterange.py.orig	2012-09-07 16:48:30.996446789 -0700
+++ /usr/share/pyshared/webob/byterange.py	2012-09-07 17:00:40.188476542 -0700
@@ -36,7 +36,7 @@
         if end is None:
             end = length
             if start < 0:
-                start += length
+                start = max(0, start + length)
         if _is_content_range_valid(start, end, length):
             stop = min(end, length)
             return (start, stop)