diff --git a/pywb/utils/binsearch.py b/pywb/utils/binsearch.py
index f605709a..6f0b431e 100644
--- a/pywb/utils/binsearch.py
+++ b/pywb/utils/binsearch.py
@@ -4,6 +4,13 @@ Utility functions for performing binary search over a sorted text file
 
 from collections import deque
 import itertools
+import six
+
+import sys
+
+if six.PY3:
+    def cmp(a, b):
+        return (a > b) - (a < b)
 
 
 #=================================================================
@@ -18,10 +25,10 @@ def binsearch_offset(reader, key, compare_func=cmp, block_size=8192):
     min_ = 0
 
     reader.seek(0, 2)
-    max_ = reader.tell() / block_size
+    max_ = int(reader.tell() / block_size)
 
     while max_ - min_ > 1:
-        mid = min_ + ((max_ - min_) / 2)
+        mid = int(min_ + ((max_ - min_) / 2))
         reader.seek(mid * block_size)
 
         if mid > 0:
@@ -135,7 +142,7 @@ def iter_prefix(reader, key):
 
 
 #=================================================================
-def iter_exact(reader, key, token=' '):
+def iter_exact(reader, key, token=b' '):
     """
     Create an iterator which iterates over lines where the first field matches
     the 'key', equivalent to token + sep prefix.
diff --git a/pywb/utils/bufferedreaders.py b/pywb/utils/bufferedreaders.py
index a895b490..f3268c58 100644
--- a/pywb/utils/bufferedreaders.py
+++ b/pywb/utils/bufferedreaders.py
@@ -120,7 +120,7 @@ class BufferedReader(object):
         call will fill buffer anew.
         """
         if length == 0:
-            return ''
+            return b''
 
         self._fillbuff()
         buff = self.buff.read(length)
@@ -134,13 +134,13 @@ class BufferedReader(object):
         at buffer boundary.
         """
         if length == 0:
-            return ''
+            return b''
 
         self._fillbuff()
         linebuff = self.buff.readline(length)
 
         # we may be at a boundary
-        while not linebuff.endswith('\n'):
+        while not linebuff.endswith(b'\n'):
             if length:
                 length -= len(linebuff)
                 if length <= 0:
@@ -195,7 +195,7 @@ class DecompressingBufferedReader(BufferedReader):
 
 #=================================================================
 class ChunkedDataException(Exception):
-    def __init__(self, msg, data=''):
+    def __init__(self, msg, data=b''):
         Exception.__init__(self, msg)
         self.data = data
 
@@ -249,19 +249,19 @@ class ChunkedDataReader(BufferedReader):
     def _try_decode(self, length_header):
         # decode length header
         try:
-            chunk_size = int(length_header.strip().split(';')[0], 16)
+            chunk_size = int(length_header.strip().split(b';')[0], 16)
         except ValueError:
-            raise ChunkedDataException("Couldn't decode length header " +
+            raise ChunkedDataException(b"Couldn't decode length header " +
                                        length_header)
 
         if not chunk_size:
             # chunk_size 0 indicates end of file
             self.all_chunks_read = True
-            self._process_read('')
+            self._process_read(b'')
             return
 
         data_len = 0
-        data = ''
+        data = b''
 
         # read chunk
         while data_len < chunk_size:
@@ -285,8 +285,8 @@ class ChunkedDataReader(BufferedReader):
         # it should end in \r\n
         if not self.all_chunks_read:
             clrf = self.stream.read(2)
-            if clrf != '\r\n':
-                raise ChunkedDataException("Chunk terminator not found.",
+            if clrf != b'\r\n':
+                raise ChunkedDataException(b"Chunk terminator not found.",
                                            data)
 
         # hand to base class for further processing
diff --git a/pywb/utils/canonicalize.py b/pywb/utils/canonicalize.py
index 7bbbf7ed..c64dfc04 100644
--- a/pywb/utils/canonicalize.py
+++ b/pywb/utils/canonicalize.py
@@ -2,9 +2,9 @@
 """
 
 import surt
-import urlparse
+import six.moves.urllib.parse as urlparse
 
-from wbexception import BadRequestException
+from pywb.utils.wbexception import BadRequestException
 
 
 #=================================================================
@@ -128,11 +128,11 @@ def calc_search_range(url, match_type, surt_ordered=True, url_canon=None):
     ('example.com/', 'example.com0')
 
     # errors: domain range not supported
-    >>> calc_search_range('http://example.com/path/file.html', 'domain', False)
+    >>> calc_search_range('http://example.com/path/file.html', 'domain', False)  # doctest: +IGNORE_EXCEPTION_DETAIL
     Traceback (most recent call last):
     UrlCanonicalizeException: matchType=domain unsupported for non-surt
 
-    >>> calc_search_range('http://example.com/path/file.html', 'blah', False)
+    >>> calc_search_range('http://example.com/path/file.html', 'blah', False)   # doctest: +IGNORE_EXCEPTION_DETAIL
     Traceback (most recent call last):
     UrlCanonicalizeException: Invalid match_type: blah
 
diff --git a/pywb/utils/dsrules.py b/pywb/utils/dsrules.py
index 7c0a8cf9..af509987 100644
--- a/pywb/utils/dsrules.py
+++ b/pywb/utils/dsrules.py
@@ -1,5 +1,5 @@
 import pkgutil
-from loaders import load_yaml_config
+from pywb.utils.loaders import load_yaml_config
 
 
 #=================================================================
diff --git a/pywb/utils/loaders.py b/pywb/utils/loaders.py
index f4a2e264..2a81b8d2 100644
--- a/pywb/utils/loaders.py
+++ b/pywb/utils/loaders.py
@@ -5,12 +5,15 @@ local and remote access
 
 import os
 import hmac
-import urllib
-#import urllib2
 import requests
-import urlparse
+
+import six
+import six.moves.urllib.request as urllib_req
+import six.moves.urllib.parse as urlparse
+
 import time
 import pkg_resources
+
 from io import open, BytesIO
 
 try:
@@ -30,7 +33,7 @@ def to_file_url(filename):
     """ Convert a filename to a file:// url
     """
     url = os.path.abspath(filename)
-    url = urlparse.urljoin('file:', urllib.pathname2url(url))
+    url = urlparse.urljoin('file:', urllib_req.pathname2url(url))
     return url
 
 
@@ -80,7 +83,7 @@ def extract_post_query(method, mime, length, stream, buffered_stream=None):
         buffered_stream.write(post_query)
         buffered_stream.seek(0)
 
-    post_query = urllib.unquote_plus(post_query)
+    post_query = urlparse.unquote_plus(post_query)
     return post_query
 
 
@@ -210,7 +213,7 @@ class LocalFileLoader(object):
         # convert to filename
         if url.startswith('file://'):
             file_only = True
-            url = urllib.url2pathname(url[len('file://'):])
+            url = urllib_req.url2pathname(url[len('file://'):])
 
         try:
             # first, try as file
@@ -253,7 +256,7 @@ class HttpLoader(object):
             headers['Range'] = BlockLoader._make_range_header(offset, length)
 
         if self.cookie_maker:
-            if isinstance(self.cookie_maker, basestring):
+            if isinstance(self.cookie_maker, six.string_types):
                 headers['Cookie'] = self.cookie_maker
             else:
                 headers['Cookie'] = self.cookie_maker.make()
@@ -311,14 +314,14 @@ class HMACCookieMaker(object):
         self.duration = duration
 
     def make(self, extra_id=''):
-        expire = str(long(time.time() + self.duration))
+        expire = str(int(time.time() + self.duration))
 
         if extra_id:
             msg = extra_id + '-' + expire
         else:
             msg = expire
 
-        hmacdigest = hmac.new(self.key, msg)
+        hmacdigest = hmac.new(self.key.encode('utf-8'), msg.encode('utf-8'))
         hexdigest = hmacdigest.hexdigest()
 
         if extra_id:
@@ -349,7 +352,7 @@ class LimitReader(object):
             length = self.limit
 
         if length == 0:
-            return ''
+            return b''
 
         buff = self.stream.read(length)
         self.limit -= len(buff)
@@ -362,7 +365,7 @@ class LimitReader(object):
             length = self.limit
 
         if length == 0:
-            return ''
+            return b''
 
         buff = self.stream.readline(length)
         self.limit -= len(buff)
diff --git a/pywb/utils/statusandheaders.py b/pywb/utils/statusandheaders.py
index a9740735..4327398c 100644
--- a/pywb/utils/statusandheaders.py
+++ b/pywb/utils/statusandheaders.py
@@ -4,6 +4,7 @@ Representation and parsing of HTTP-style status + headers
 
 import pprint
 from copy import copy
+from six.moves import range
 
 
 #=================================================================
@@ -36,7 +37,7 @@ class StatusAndHeaders(object):
         return old header value, if any
         """
         name_lower = name.lower()
-        for index in xrange(len(self.headers) - 1, -1, -1):
+        for index in range(len(self.headers) - 1, -1, -1):
             curr_name, curr_value = self.headers[index]
             if curr_name.lower() == name_lower:
                 self.headers[index] = (curr_name, value)
@@ -52,7 +53,7 @@ class StatusAndHeaders(object):
         """
         header_dict = copy(header_dict)
 
-        for index in xrange(len(self.headers) - 1, -1, -1):
+        for index in range(len(self.headers) - 1, -1, -1):
             curr_name, curr_value = self.headers[index]
             name_lower = curr_name.lower()
             if name_lower in header_dict:
@@ -68,7 +69,7 @@ class StatusAndHeaders(object):
         return True if header removed, False otherwise
         """
         name_lower = name.lower()
-        for index in xrange(len(self.headers) - 1, -1, -1):
+        for index in range(len(self.headers) - 1, -1, -1):
             if self.headers[index][0].lower() == name_lower:
                 del self.headers[index]
                 return True
@@ -93,7 +94,7 @@ class StatusAndHeaders(object):
             code = int(code)
             assert(code > 0)
             return True
-        except ValueError, AssertionError:
+        except(ValueError, AssertionError):
             self.statusline = valid_statusline
             return False
 
diff --git a/pywb/utils/test/test_binsearch.py b/pywb/utils/test/test_binsearch.py
index 7b5cbb3c..4666b497 100644
--- a/pywb/utils/test/test_binsearch.py
+++ b/pywb/utils/test/test_binsearch.py
@@ -82,13 +82,13 @@ test_cdx_dir = get_test_dir() + 'cdx/'
 
 def print_binsearch_results(key, iter_func):
     with open(test_cdx_dir + 'iana.cdx', 'rb') as cdx:
-        for line in iter_func(cdx, key):
-            print line
+        for line in iter_func(cdx, key.encode('utf-8')):
+            print(line.decode('utf-8'))
 
 def print_binsearch_results_range(key, end_key, iter_func, prev_size=0):
     with open(test_cdx_dir + 'iana.cdx', 'rb') as cdx:
-        for line in iter_func(cdx, key, end_key, prev_size=prev_size):
-            print line
+        for line in iter_func(cdx, key.encode('utf-8'), end_key.encode('utf-8'), prev_size=prev_size):
+            print(line.decode('utf-8'))
 
 
 if __name__ == "__main__":
diff --git a/pywb/utils/test/test_bufferedreaders.py b/pywb/utils/test/test_bufferedreaders.py
index 0f96de84..9f4fd54a 100644
--- a/pywb/utils/test/test_bufferedreaders.py
+++ b/pywb/utils/test/test_bufferedreaders.py
@@ -3,19 +3,19 @@ r"""
 #=================================================================
 
 # DecompressingBufferedReader readline()
->>> DecompressingBufferedReader(open(test_cdx_dir + 'iana.cdx', 'rb')).readline()
+>>> print_str(DecompressingBufferedReader(open(test_cdx_dir + 'iana.cdx', 'rb')).readline())
 ' CDX N b a m s k r M S V g\n'
 
 # detect not compressed
->>> DecompressingBufferedReader(open(test_cdx_dir + 'iana.cdx', 'rb'), decomp_type = 'gzip').readline()
+>>> print_str(DecompressingBufferedReader(open(test_cdx_dir + 'iana.cdx', 'rb'), decomp_type = 'gzip').readline())
 ' CDX N b a m s k r M S V g\n'
 
 # decompress with on the fly compression, default gzip compression
->>> DecompressingBufferedReader(BytesIO(compress('ABC\n1234\n'))).read()
+>>> print_str(DecompressingBufferedReader(BytesIO(compress('ABC\n1234\n'))).read())
 'ABC\n1234\n'
 
 # decompress with on the fly compression, default 'inflate' compression
->>> DecompressingBufferedReader(BytesIO(compress_alt('ABC\n1234\n')), decomp_type='deflate').read()
+>>> print_str(DecompressingBufferedReader(BytesIO(compress_alt('ABC\n1234\n')), decomp_type='deflate').read())
 'ABC\n1234\n'
 
 # error: invalid compress type
@@ -23,26 +23,18 @@ r"""
 Traceback (most recent call last):
 Exception: Decompression type not supported: bzip2
 
-# error: compressed member, followed by not compressed -- considered invalid
->>> x = DecompressingBufferedReader(BytesIO(compress('ABC') + '123'), decomp_type = 'gzip')
->>> b = x.read()
->>> b = x.read_next_member()
->>> x.read()
-Traceback (most recent call last):
-error: Error -3 while decompressing: incorrect header check
-
 # invalid output when reading compressed data as not compressed
->>> DecompressingBufferedReader(BytesIO(compress('ABC')), decomp_type = None).read() != 'ABC'
+>>> DecompressingBufferedReader(BytesIO(compress('ABC')), decomp_type = None).read() != b'ABC'
 True
 
 
 # DecompressingBufferedReader readline() with decompression (zipnum file, no header)
->>> DecompressingBufferedReader(open(test_zip_dir + 'zipnum-sample.cdx.gz', 'rb'), decomp_type = 'gzip').readline()
+>>> print_str(DecompressingBufferedReader(open(test_zip_dir + 'zipnum-sample.cdx.gz', 'rb'), decomp_type = 'gzip').readline())
 'com,example)/ 20140127171200 http://example.com text/html 200 B2LTWWPUOYAH7UIPQ7ZUPQ4VMBSVC36A - - 1046 334 dupes.warc.gz\n'
 
 # test very small block size
->>> dbr = DecompressingBufferedReader(BytesIO('ABCDEFG\nHIJKLMN\nOPQR\nXYZ'), block_size = 3)
->>> dbr.readline(); dbr.readline(4); dbr.readline(); dbr.readline(); dbr.readline(2); dbr.readline(); dbr.readline()
+>>> dbr = DecompressingBufferedReader(BytesIO(b'ABCDEFG\nHIJKLMN\nOPQR\nXYZ'), block_size = 3)
+>>> print_str(dbr.readline()); print_str(dbr.readline(4)); print_str(dbr.readline()); print_str(dbr.readline()); print_str(dbr.readline(2)); print_str(dbr.readline()); print_str(dbr.readline())
 'ABCDEFG\n'
 'HIJK'
 'LMN\n'
@@ -52,8 +44,8 @@ True
 ''
 
 # test zero length reads
->>> x = DecompressingBufferedReader(LimitReader(BytesIO('\r\n'), 1))
->>> x.readline(0); x.read(0)
+>>> x = DecompressingBufferedReader(LimitReader(BytesIO(b'\r\n'), 1))
+>>> print_str(x.readline(0)); print_str(x.read(0))
 ''
 ''
 
@@ -61,71 +53,69 @@ True
 #=================================================================
 
 Properly formatted chunked data:
->>> c = ChunkedDataReader(BytesIO("4\r\n1234\r\n0\r\n\r\n"));
->>> c.read() + c.read() + c.read()
+>>> c = ChunkedDataReader(BytesIO(b"4\r\n1234\r\n0\r\n\r\n"));
+>>> print_str(c.read() + c.read() + c.read())
 '1234'
 
 Non-chunked data:
->>> ChunkedDataReader(BytesIO("xyz123!@#")).read()
+>>> print_str(ChunkedDataReader(BytesIO(b"xyz123!@#")).read())
 'xyz123!@#'
 
 Non-chunked, compressed data, specify decomp_type
->>> ChunkedDataReader(BytesIO(compress('ABCDEF')), decomp_type='gzip').read()
+>>> print_str(ChunkedDataReader(BytesIO(compress('ABCDEF')), decomp_type='gzip').read())
 'ABCDEF'
 
 Non-chunked, compressed data, specifiy compression seperately
->>> c = ChunkedDataReader(BytesIO(compress('ABCDEF'))); c.set_decomp('gzip'); c.read()
+>>> c = ChunkedDataReader(BytesIO(compress('ABCDEF'))); c.set_decomp('gzip'); print_str(c.read())
 'ABCDEF'
 
 Non-chunked, compressed data, wrap in DecompressingBufferedReader
->>> DecompressingBufferedReader(ChunkedDataReader(BytesIO(compress('\nABCDEF\nGHIJ')))).read()
+>>> print_str(DecompressingBufferedReader(ChunkedDataReader(BytesIO(compress('\nABCDEF\nGHIJ')))).read())
 '\nABCDEF\nGHIJ'
 
 Chunked compressed data
 Split compressed stream into 10-byte chunk and a remainder chunk
 >>> b = compress('ABCDEFGHIJKLMNOP')
 >>> l = len(b)
->>> in_ = format(10, 'x') + "\r\n" + b[:10] + "\r\n" + format(l - 10, 'x') + "\r\n" + b[10:] + "\r\n0\r\n\r\n"
+>>> in_ = format(10, 'x').encode('utf-8') + b"\r\n" + b[:10] + b"\r\n" + format(l - 10, 'x').encode('utf-8') + b"\r\n" + b[10:] + b"\r\n0\r\n\r\n"
 >>> c = ChunkedDataReader(BytesIO(in_), decomp_type='gzip')
->>> c.read()
+>>> print_str(c.read())
 'ABCDEFGHIJKLMNOP'
 
 Starts like chunked data, but isn't:
->>> c = ChunkedDataReader(BytesIO("1\r\nxyz123!@#"));
->>> c.read() + c.read()
+>>> c = ChunkedDataReader(BytesIO(b"1\r\nxyz123!@#"));
+>>> print_str(c.read() + c.read())
 '1\r\nx123!@#'
 
 Chunked data cut off part way through:
->>> c = ChunkedDataReader(BytesIO("4\r\n1234\r\n4\r\n12"));
->>> c.read() + c.read()
+>>> c = ChunkedDataReader(BytesIO(b"4\r\n1234\r\n4\r\n12"));
+>>> print_str(c.read() + c.read())
 '123412'
 
 Zero-Length chunk:
->>> ChunkedDataReader(BytesIO("0\r\n\r\n")).read()
+>>> print_str(ChunkedDataReader(BytesIO(b"0\r\n\r\n")).read())
 ''
 
-Chunked data cut off with exceptions
->>> c = ChunkedDataReader(BytesIO("4\r\n1234\r\n4\r\n12"), raise_exceptions=True)
->>> c.read() + c.read()
-Traceback (most recent call last):
-ChunkedDataException: Ran out of data before end of chunk
-
 """
 
 from io import BytesIO
-from pywb.utils.bufferedreaders import ChunkedDataReader
+from pywb.utils.bufferedreaders import ChunkedDataReader, ChunkedDataException
 from pywb.utils.bufferedreaders import DecompressingBufferedReader
 from pywb.utils.loaders import LimitReader
 
 from pywb import get_test_dir
 
+import six
+
 import zlib
+import pytest
 
 test_cdx_dir = get_test_dir() + 'cdx/'
 test_zip_dir = get_test_dir() + 'zipcdx/'
 
 
 def compress(buff):
+    buff = buff.encode('utf-8')
     compressobj = zlib.compressobj(6, zlib.DEFLATED, zlib.MAX_WBITS + 16)
     compressed = compressobj.compress(buff)
     compressed += compressobj.flush()
@@ -134,6 +124,7 @@ def compress(buff):
 
 # plain "inflate"
 def compress_alt(buff):
+    buff = buff.encode('utf-8')
     compressobj = zlib.compressobj(6, zlib.DEFLATED)
     compressed = compressobj.compress(buff)
     compressed += compressobj.flush()
@@ -142,6 +133,32 @@ def compress_alt(buff):
 
     return compressed
 
+
+# Errors
+
+def test_err_compress_mix():
+    # error: compressed member, followed by not compressed -- considered invalid
+    x = DecompressingBufferedReader(BytesIO(compress('ABC') + b'123'), decomp_type = 'gzip')
+    b = x.read()
+    b = x.read_next_member()
+    with pytest.raises(zlib.error):
+        x.read()
+    #error: Error -3 while decompressing: incorrect header check
+
+def test_err_chunk_cut_off():
+    # Chunked data cut off with exceptions
+    c = ChunkedDataReader(BytesIO(b"4\r\n1234\r\n4\r\n12"), raise_exceptions=True)
+    with pytest.raises(ChunkedDataException):
+        c.read() + c.read()
+    #ChunkedDataException: Ran out of data before end of chunk
+
+
+
+def print_str(string):
+    return string.decode('utf-8') if six.PY3 else string
+
+
+
 if __name__ == "__main__":
     import doctest
     doctest.testmod()
diff --git a/pywb/utils/test/test_loaders.py b/pywb/utils/test/test_loaders.py
index 0dba90be..6275720a 100644
--- a/pywb/utils/test/test_loaders.py
+++ b/pywb/utils/test/test_loaders.py
@@ -1,30 +1,30 @@
 #=================================================================
 r"""
 # LimitReader Tests
->>> LimitReader(BytesIO('abcdefghjiklmnopqrstuvwxyz'), 10).read(26)
+>>> LimitReader(StringIO('abcdefghjiklmnopqrstuvwxyz'), 10).read(26)
 'abcdefghji'
 
->>> LimitReader(BytesIO('abcdefghjiklmnopqrstuvwxyz'), 8).readline(26)
+>>> LimitReader(StringIO('abcdefghjiklmnopqrstuvwxyz'), 8).readline(26)
 'abcdefgh'
 
->>> LimitReader.wrap_stream(LimitReader(BytesIO('abcdefghjiklmnopqrstuvwxyz'), 8), 4).readline(26)
+>>> LimitReader.wrap_stream(LimitReader(StringIO('abcdefghjiklmnopqrstuvwxyz'), 8), 4).readline(26)
 'abcd'
 
->>> read_multiple(LimitReader(BytesIO('abcdefghjiklmnopqrstuvwxyz'), 10), [2, 2, 20])
+>>> read_multiple(LimitReader(StringIO('abcdefghjiklmnopqrstuvwxyz'), 10), [2, 2, 20])
 'efghji'
 
 # zero-length read
->>> LimitReader(BytesIO('a'), 0).readline(0)
+>>> print_str(LimitReader(StringIO('a'), 0).readline(0))
 ''
 
 # don't wrap if invalid length
->>> b = BytesIO('b')
+>>> b = StringIO('b')
 >>> LimitReader.wrap_stream(b, 'abc') == b
 True
 
 # BlockLoader Tests (includes LimitReader)
 # Ensure attempt to read more than 100 bytes, reads exactly 100 bytes
->>> len(BlockLoader().load(test_cdx_dir + 'iana.cdx', 0, 100).read('400'))
+>>> len(BlockLoader().load(test_cdx_dir + 'iana.cdx', 0, 100).read(400))
 100
 
 # no length specified, read full amount requested
@@ -32,26 +32,26 @@ True
 400
 
 # no such file
->>> len(BlockLoader().load('_x_no_such_file_', 0, 100).read('400'))
+#>>> len(BlockLoader().load('_x_no_such_file_', 0, 100).read(400))  # doctest: +IGNORE_EXCEPTION_DETAIL
 Traceback (most recent call last):
 IOError: [Errno 2] No such file or directory: '_x_no_such_file_'
 
 # HMAC Cookie Maker
->>> BlockLoader(HMACCookieMaker('test', 'test', 5)).load('http://example.com', 41, 14).read()
+>>> print_str(BlockLoader(HMACCookieMaker('test', 'test', 5)).load('http://example.com', 41, 14).read())
 'Example Domain'
 
 # fixed cookie, range request
->>> BlockLoader('some=value').load('http://example.com', 41, 14).read()
+>>> print_str(BlockLoader('some=value').load('http://example.com', 41, 14).read())
 'Example Domain'
 
 # range request
->>> BlockLoader().load('http://example.com', 1262).read()
+>>> print_str(BlockLoader().load('http://example.com', 1262).read())
 '</html>\n'
 
 # unknown loader error
->>> BlockLoader().load('foo://example.com', 10).read()
-Traceback (most recent call last):
-IOError: No Loader for type: foo
+#>>> BlockLoader().load('foo://example.com', 10).read()  # doctest: +IGNORE_EXCEPTION_DETAIL
+#Traceback (most recent call last):
+#IOError: No Loader for type: foo
 
 # test with extra id, ensure 4 parts of the A-B=C-D form are present
 >>> len(re.split('[-=]', HMACCookieMaker('test', 'test', 5).make('extra')))
@@ -84,42 +84,42 @@ IOError: No Loader for type: foo
 
 # correct POST data
 >>> post_data = 'foo=bar&dir=%2Fbaz'
->>> extract_post_query('POST', 'application/x-www-form-urlencoded', len(post_data), BytesIO(post_data))
+>>> extract_post_query('POST', 'application/x-www-form-urlencoded', len(post_data), StringIO(post_data))
 'foo=bar&dir=/baz'
 
 # unsupported method
->>> extract_post_query('PUT', 'application/x-www-form-urlencoded', len(post_data), BytesIO(post_data))
+>>> extract_post_query('PUT', 'application/x-www-form-urlencoded', len(post_data), StringIO(post_data))
 
 # unsupported type
->>> extract_post_query('POST', 'text/plain', len(post_data), BytesIO(post_data))
+>>> extract_post_query('POST', 'text/plain', len(post_data), StringIO(post_data))
 
 # invalid length
->>> extract_post_query('POST', 'application/x-www-form-urlencoded', 'abc', BytesIO(post_data))
->>> extract_post_query('POST', 'application/x-www-form-urlencoded', 0, BytesIO(post_data))
+>>> extract_post_query('POST', 'application/x-www-form-urlencoded', 'abc', StringIO(post_data))
+>>> extract_post_query('POST', 'application/x-www-form-urlencoded', 0, StringIO(post_data))
 
 # length too short
->>> extract_post_query('POST', 'application/x-www-form-urlencoded', len(post_data) - 4, BytesIO(post_data))
+>>> extract_post_query('POST', 'application/x-www-form-urlencoded', len(post_data) - 4, StringIO(post_data))
 'foo=bar&dir=%2'
 
 # length too long
->>> extract_post_query('POST', 'application/x-www-form-urlencoded', len(post_data) + 4, BytesIO(post_data))
+>>> extract_post_query('POST', 'application/x-www-form-urlencoded', len(post_data) + 4, StringIO(post_data))
 'foo=bar&dir=/baz'
 
 
 # test read_last_line
->>> read_last_line(BytesIO('A\nB\nC'))
+>>> print_str(read_last_line(BytesIO(b'A\nB\nC')))
 'C'
 
->>> read_last_line(BytesIO('Some Line\nLonger Line\nLongest Last Line LL'), offset=8)
+>>> print_str(read_last_line(BytesIO(b'Some Line\nLonger Line\nLongest Last Line LL'), offset=8))
 'Longest Last Line LL'
 
->>> read_last_line(BytesIO('A\nBC'))
+>>> print_str(read_last_line(BytesIO(b'A\nBC')))
 'BC'
 
->>> read_last_line(BytesIO('A\nBC\n'))
+>>> print_str(read_last_line(BytesIO(b'A\nBC\n')))
 'BC\n'
 
->>> read_last_line(BytesIO('ABC'))
+>>> print_str(read_last_line(BytesIO(b'ABC')))
 'ABC'
 
 """
@@ -130,7 +130,10 @@ import re
 import os
 import pytest
 
+import six
+from six import StringIO
 from io import BytesIO
+
 from pywb.utils.loaders import BlockLoader, HMACCookieMaker, to_file_url
 from pywb.utils.loaders import LimitReader, extract_client_cookie, extract_post_query
 from pywb.utils.loaders import append_post_query, read_last_line
@@ -165,8 +168,27 @@ def test_s3_read_1():
     assert len(buff) == 2526
 
     reader = DecompressingBufferedReader(BytesIO(buff))
-    assert reader.readline() == 'WARC/1.0\r\n'
-    assert reader.readline() == 'WARC-Type: response\r\n'
+    assert reader.readline() == b'WARC/1.0\r\n'
+    assert reader.readline() == b'WARC-Type: response\r\n'
+
+
+# Error
+def test_err_no_such_file():
+    # no such file
+    with pytest.raises(IOError):
+        len(BlockLoader().load('_x_no_such_file_', 0, 100).read('400'))
+
+
+def test_err_unknown_loader():
+    # unknown loader error
+    with pytest.raises(IOError):
+        BlockLoader().load('foo://example.com', 10).read()
+#IOError: No Loader for type: foo
+
+
+def print_str(string):
+    return string.decode('utf-8') if six.PY3 else string
+
 
 if __name__ == "__main__":
     import doctest
diff --git a/pywb/utils/test/test_statusandheaders.py b/pywb/utils/test/test_statusandheaders.py
index d4efa72f..706ac001 100644
--- a/pywb/utils/test/test_statusandheaders.py
+++ b/pywb/utils/test/test_statusandheaders.py
@@ -1,5 +1,5 @@
 """
->>> st1 = StatusAndHeadersParser(['HTTP/1.0']).parse(BytesIO(status_headers_1))
+>>> st1 = StatusAndHeadersParser(['HTTP/1.0']).parse(StringIO(status_headers_1))
 >>> st1
 StatusAndHeaders(protocol = 'HTTP/1.0', statusline = '200 OK', headers = [ ('Content-Type', 'ABC'),
   ('Some', 'Value'),
@@ -12,30 +12,30 @@ StatusAndHeaders(protocol = '', statusline = '206 Partial Content', headers = [
   ('Accept-Ranges', 'bytes')])
 
 # other protocol expected
->>> StatusAndHeadersParser(['Other']).parse(BytesIO(status_headers_1))
+>>> StatusAndHeadersParser(['Other']).parse(StringIO(status_headers_1))  # doctest: +IGNORE_EXCEPTION_DETAIL
 Traceback (most recent call last):
 StatusAndHeadersParserException: Expected Status Line starting with ['Other'] - Found: HTTP/1.0 200 OK
 
->>> StatusAndHeadersParser(['Other'], verify=False).parse(BytesIO(status_headers_1))
+>>> StatusAndHeadersParser(['Other'], verify=False).parse(StringIO(status_headers_1))
 StatusAndHeaders(protocol = 'HTTP/1.0', statusline = '200 OK', headers = [ ('Content-Type', 'ABC'),
   ('Some', 'Value'),
   ('Multi-Line', 'Value1    Also This')])
 
 
 # verify protocol line
->>> StatusAndHeadersParser(['HTTP/1.0'], verify=True).parse(BytesIO(unknown_protocol_headers))
+>>> StatusAndHeadersParser(['HTTP/1.0'], verify=True).parse(StringIO(unknown_protocol_headers))  # doctest: +IGNORE_EXCEPTION_DETAIL
 Traceback (most recent call last):
 StatusAndHeadersParserException: Expected Status Line starting with ['HTTP/1.0'] - Found: OtherBlah
 
 
 # allow unexpected/invalid protocol line
->>> StatusAndHeadersParser(['HTTP/1.0'], verify=False).parse(BytesIO(unknown_protocol_headers))
+>>> StatusAndHeadersParser(['HTTP/1.0'], verify=False).parse(StringIO(unknown_protocol_headers))
 StatusAndHeaders(protocol = 'OtherBlah', statusline = 'OtherBlah', headers = [('Foo', 'Bar')])
 
 
 
 # test equality op
->>> st1 == StatusAndHeadersParser(['HTTP/1.0']).parse(BytesIO(status_headers_1))
+>>> st1 == StatusAndHeadersParser(['HTTP/1.0']).parse(StringIO(status_headers_1))
 True
 
 # replace header, print new headers
@@ -55,15 +55,15 @@ True
 False
 
 # empty
->>> st2 = StatusAndHeadersParser(['HTTP/1.0']).parse(BytesIO(status_headers_2)); x = st2.validate_statusline('204 No Content'); st2
+>>> st2 = StatusAndHeadersParser(['HTTP/1.0']).parse(StringIO(status_headers_2)); x = st2.validate_statusline('204 No Content'); st2
 StatusAndHeaders(protocol = '', statusline = '204 No Content', headers = [])
 
 
->>> StatusAndHeadersParser(['HTTP/1.0']).parse(BytesIO(status_headers_3))
+>>> StatusAndHeadersParser(['HTTP/1.0']).parse(StringIO(status_headers_3))
 StatusAndHeaders(protocol = 'HTTP/1.0', statusline = '204 Empty', headers = [('Content-Type', 'Value'), ('Content-Length', '0')])
 
 # case-insensitive match
->>> StatusAndHeadersParser(['HTTP/1.0']).parse(BytesIO(status_headers_4))
+>>> StatusAndHeadersParser(['HTTP/1.0']).parse(StringIO(status_headers_4))
 StatusAndHeaders(protocol = 'HTTP/1.0', statusline = '204 empty', headers = [('Content-Type', 'Value'), ('Content-Length', '0')])
 
 
@@ -71,7 +71,8 @@ StatusAndHeaders(protocol = 'HTTP/1.0', statusline = '204 empty', headers = [('C
 
 
 from pywb.utils.statusandheaders import StatusAndHeadersParser, StatusAndHeaders
-from io import BytesIO
+#from io import StringIO
+from six import StringIO
 
 
 status_headers_1 = "\
diff --git a/pywb/utils/timeutils.py b/pywb/utils/timeutils.py
index ae2406e1..181ca2c7 100644
--- a/pywb/utils/timeutils.py
+++ b/pywb/utils/timeutils.py
@@ -7,7 +7,7 @@ import re
 import time
 import datetime
 import calendar
-from itertools import imap
+from six.moves import map
 from email.utils import parsedate, formatdate
 
 #=================================================================
@@ -36,7 +36,7 @@ def iso_date_to_datetime(string):
     if nums[-1] == '':
         nums = nums[:-1]
 
-    the_datetime = datetime.datetime(*imap(int, nums))
+    the_datetime = datetime.datetime(*map(int, nums))
     return the_datetime
 
 
diff --git a/setup.py b/setup.py
index 1ce5dec0..a5514a71 100755
--- a/setup.py
+++ b/setup.py
@@ -47,7 +47,7 @@ setup(
     long_description=long_description,
     license='GPL',
     packages=find_packages(),
-    zip_safe=True,
+    zip_safe=False,
     provides=[
         'pywb',
         'pywb.utils',
@@ -73,11 +73,12 @@ setup(
             glob.glob('sample_archive/text_content/*')),
         ],
     install_requires=[
+        'six'
         'chardet',
         'requests',
         'redis',
         'jinja2',
-        'surt==0.2',
+        'surt==0.3b4',
         'pyyaml',
         'watchdog',
         'webencodings',