diff --git a/Makefile b/Makefile
index 9ee85c2..eb8cf8b 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,8 @@
 MODULES=pasn1.py
+VIRTUALENV?=virtualenv-3.7
 
 test:
-	(echo $(MODULES) | entr sh -c 'python -m coverage run -m unittest $(basename $(MODULES)) && coverage report -m')
+	(echo $(MODULES) | entr sh -c 'python -m coverage run -m unittest $(basename $(MODULES)) && coverage report --omit=p/\* -m -i')
+
+env:
+	($(VIRTUALENV) p && . ./p/bin/activate && pip install -r requirements.txt)
diff --git a/pasn1.py b/pasn1.py
index 6066a0a..5a40b09 100644
--- a/pasn1.py
+++ b/pasn1.py
@@ -43,18 +43,22 @@ __license__ = '2-clause BSD license'
 # either expressed or implied, of the Project.
 
 import datetime
+import functools
 import math
 import os
 import sys
 import unittest
 
+if sys.version_info.major != 3: # pragma: no cover
+	raise RuntimeError('this module only supports python 3')
+
 __all__ = [ 'dumps', 'loads', 'ASN1Coder' ]
 
-def _numtostr(n):
+def _numtobytes(n):
 	hs = '%x' % n
 	if len(hs) & 1 == 1:
 		hs = '0' + hs
-	bs = hs.decode('hex')
+	bs = bytes.fromhex(hs)
 
 	return bs
 
@@ -63,30 +67,30 @@ def _encodelen(l):
 	represents l per ASN.1 rules.'''
 
 	if l < 128:
-		return chr(l)
+		return bytes([l])
 
-	bs = _numtostr(l)
-	return chr(len(bs) | 0x80) + bs
+	bs = _numtobytes(l)
+	return bytes([len(bs) | 0x80]) + bs
 
 def _decodelen(d, pos=0):
 	'''Returns the length, and number of bytes required.'''
 
-	odp = ord(d[pos])
+	odp = d[pos]
 	if odp < 128:
-		return ord(d[pos]), 1
+		return d[pos], 1
 	else:
 		l = odp & 0x7f
-		return int(d[pos + 1:pos + 1 + l].encode('hex'), 16), l + 1
+		return int(d[pos + 1:pos + 1 + l].hex(), 16), l + 1
 
 class Test_codelen(unittest.TestCase):
 	_testdata = [
-		(2, '\x02'),
-		(127, '\x7f'),
-		(128, '\x81\x80'),
-		(255, '\x81\xff'),
-		(256, '\x82\x01\x00'),
-		(65536-1, '\x82\xff\xff'),
-		(65536, '\x83\x01\x00\x00'),
+		(2, b'\x02'),
+		(127, b'\x7f'),
+		(128, b'\x81\x80'),
+		(255, b'\x81\xff'),
+		(256, b'\x82\x01\x00'),
+		(65536-1, b'\x82\xff\xff'),
+		(65536, b'\x83\x01\x00\x00'),
 	]
 
 	def test_el(self):
@@ -101,7 +105,7 @@ def _splitfloat(f):
 		m *= 2
 		e -= 1
 
-	return m, e
+	return math.trunc(m), e
 
 class TestSplitFloat(unittest.TestCase):
 	def test_sf(self):
@@ -124,7 +128,7 @@ class ASN1Coder(object):
 			'int': compatible w/ int
 			'list': __iter__
 			'set': __iter__
-			'bytes': __str__
+			'bytes': __str__ # XXX what is correct here
 			'null': no method needed
 			'unicode': encode method returns UTF-8 encoded bytes
 			'datetime': strftime and microsecond
@@ -137,28 +141,27 @@ class ASN1Coder(object):
 		float: 'float',
 		int: 'int',
 		list: 'list',
-		long: 'int',
 		set: 'set',
-		str: 'bytes',
+		bytes: 'bytes',
 		type(None): 'null',
-		unicode: 'unicode',
+		str: 'unicode',
 		#decimal.Decimal: 'float',
 		datetime.datetime: 'datetime',
 		#datetime.timedelta: 'timedelta',
 	}
 	_tagmap = {
-		'\x01':	'bool',
-		'\x02':	'int',
-		'\x04':	'bytes',
-		'\x05':	'null',
-		'\x09':	'float',
-		'\x0c':	'unicode',
-		'\x18': 'datetime',
-		'\x30':	'list',
-		'\x31': 'set',
+		b'\x01':	'bool',
+		b'\x02':	'int',
+		b'\x04':	'bytes',
+		b'\x05':	'null',
+		b'\x09':	'float',
+		b'\x0c':	'unicode',
+		b'\x18':	'datetime',
+		b'\x30':	'list',
+		b'\x31':	'set',
 	}
 
-	_typetag = dict((v, k) for k, v in _tagmap.iteritems())
+	_typetag = dict((v, k) for k, v in _tagmap.items())
 
 	@staticmethod
 	def enc_int(obj, **kwargs):
@@ -170,10 +173,10 @@ class ASN1Coder(object):
 		if obj < 0:
 			obj += 1 << (l * 8) # twos-complement conversion
 
-		v = _numtostr(obj)
+		v = _numtobytes(obj)
 		if len(v) != l:
 			# XXX - is this a problem for signed values?
-			v = '\x00' + v # add sign octect
+			v = b'\x00' + v # add sign octect
 
 		return _encodelen(l) + v
 
@@ -182,7 +185,7 @@ class ASN1Coder(object):
 		if pos == end:
 			return 0, end
 
-		v = int(d[pos:end].encode('hex'), 16)
+		v = int(bytes.hex(d[pos:end]), 16)
 		av = 1 << ((end - pos) * 8 - 1) # sign bit
 		if v > av:
 			v -= av * 2 # twos-complement conversion
@@ -191,7 +194,7 @@ class ASN1Coder(object):
 
 	@staticmethod
 	def enc_bool(obj, **kwargs):
-		return '\x01' + ('\xff' if obj else '\x00')
+		return b'\x01' + (b'\xff' if obj else b'\x00')
 
 	def dec_bool(self, d, pos, end):
 		v = self.dec_int(d, pos, end)[0]
@@ -202,14 +205,14 @@ class ASN1Coder(object):
 
 	@staticmethod
 	def enc_null(obj, **kwargs):
-		return '\x00'
+		return b'\x00'
 
 	@staticmethod
 	def dec_null(d, pos, end):
 		return None, end
 
 	def enc_list(self, obj, **kwargs):
-		r = ''.join(self.dumps(x, **kwargs) for x in obj)
+		r = b''.join(self.dumps(x, **kwargs) for x in obj)
 		return _encodelen(len(r)) + r
 
 	def dec_list(self, d, pos, end):
@@ -250,17 +253,17 @@ class ASN1Coder(object):
 	def enc_float(obj, **kwargs):
 		s = math.copysign(1, obj)
 		if math.isnan(obj):
-			return _encodelen(1) + chr(0b01000010)
+			return _encodelen(1) + bytes([0b01000010])
 		elif math.isinf(obj):
 			if s == 1:
-				return _encodelen(1) + chr(0b01000000)
+				return _encodelen(1) + bytes([0b01000000])
 			else:
-				return _encodelen(1) + chr(0b01000001)
+				return _encodelen(1) + bytes([0b01000001])
 		elif obj == 0:
 			if s == 1:
 				return _encodelen(0)
 			else:
-				return _encodelen(1) + chr(0b01000011)
+				return _encodelen(1) + bytes([0b01000011])
 
 		m, e = _splitfloat(obj)
 
@@ -279,17 +282,17 @@ class ASN1Coder(object):
 			e += 256**el	# convert negative to twos-complement
 
 		v = el - 1
-		encexp = _numtostr(e)
+		encexp = _numtobytes(e)
 
 		val |= v
-		r = chr(val) + encexp + _numtostr(m)
+		r = bytes([val]) + encexp + _numtobytes(m)
 		return _encodelen(len(r)) + r
 
 	def dec_float(self, d, pos, end):
 		if pos == end:
 			return float(0), end
 
-		v = ord(d[pos])
+		v = d[pos]
 		if v == 0b01000000:
 			return float('inf'), end
 		elif v == 0b01000001:
@@ -314,7 +317,7 @@ class ASN1Coder(object):
 
 		exp = self.dec_int(d, pexp, eexp)[0]
 
-		n = float(int(d[eexp:end].encode('hex'), 16))
+		n = float(int(bytes.hex(d[eexp:end]), 16))
 		r = n * 2 ** exp
 		if v & 0b1000000:
 			r = -r
@@ -340,7 +343,7 @@ class ASN1Coder(object):
 					pass
 
 			if self.coerce is None:
-				raise TypeError('unhandled object: %s' % `obj`)
+				raise TypeError('unhandled object: %s' % repr(obj))
 
 			tf, obj = self.coerce(obj)
 
@@ -348,7 +351,7 @@ class ASN1Coder(object):
 		return self._typetag[tf] + fun(obj, default=default)
 
 	def _loads(self, data, pos, end):
-		tag = data[pos]
+		tag = data[pos:pos + 1]
 		l, b = _decodelen(data, pos + 1)
 		if len(data) < pos + 1 + b + l:
 			raise ValueError('string not long enough')
@@ -365,12 +368,12 @@ class ASN1Coder(object):
 		if obj.microsecond:
 			ts += ('.%06d' % obj.microsecond).rstrip('0')
 		ts += 'Z'
-		return _encodelen(len(ts)) + ts
+		return _encodelen(len(ts)) + ts.encode('utf-8')
 
 	def dec_datetime(self, data, pos, end):
-		ts = data[pos:end]
-		if ts[-1] != 'Z':
-			raise ValueError('last character must be Z')
+		ts = data[pos:end].decode('ascii')
+		if ts[-1:] != 'Z':
+			raise ValueError('last character must be Z, was: %s' % repr(ts[-1]))
 
 		# Real bug is in strptime, but work around it here.
 		if ' ' in ts:
@@ -411,14 +414,14 @@ class ASN1DictCoder(ASN1Coder):
 	_typemap = ASN1Coder._typemap.copy()
 	_typemap[dict] = 'dict'
 	_tagmap = ASN1Coder._tagmap.copy()
-	_tagmap['\xe0'] = 'dict'
-	_typetag = dict((v, k) for k, v in _tagmap.iteritems())
+	_tagmap[b'\xe0'] = 'dict'
+	_typetag = dict((v, k) for k, v in _tagmap.items())
 
 	def enc_dict(self, obj, **kwargs):
 		#it = list(obj.iteritems())
 		#it.sort()
-		r = ''.join(self.dumps(k, **kwargs) + self.dumps(v, **kwargs) for k, v in
-		    obj.iteritems())
+		r = b''.join(self.dumps(k, **kwargs) + self.dumps(v, **kwargs) for k, v in
+		    obj.items())
 		return _encodelen(len(r)) + r
 
 	def dec_dict(self, d, pos, end):
@@ -441,11 +444,29 @@ _coder = ASN1DictCoder()
 dumps = _coder.dumps
 loads = _coder.loads
 
+def cmp(a, b):
+	return (a > b) - (a < b)
+
+def universal_cmp(a, b):
+	# Because Python 3 sucks, make this function that
+	# orders first based upon type, then on value.
+	if type(a) == type(b):
+		if isinstance(a, (tuple, list)):
+			for a, b in zip(a, b):
+				if a != b:
+					return universal_cmp(a, b)
+
+			#return cmp(len(a), len(b))
+		else:
+			return cmp(a, b)
+	else:
+		return id(type(a)) < id(type(b))
+
 def deeptypecmp(obj, o):
-	#print 'dtc:', `obj`, `o`
+	#print('dtc:', repr(obj), repr(o))
 	if type(obj) != type(o):
 		return False
-	if type(obj) in (str, unicode):
+	if type(obj) is str:
 		return True
 
 	if type(obj) in (list, set):
@@ -454,10 +475,8 @@ def deeptypecmp(obj, o):
 				return False
 
 	if type(obj) in (dict,):
-		itms = obj.items()
-		itms.sort()
-		nitms = o.items()
-		nitms.sort()
+		itms = sorted(obj.items(), key=functools.cmp_to_key(universal_cmp))
+		nitms = sorted(o.items(), key=functools.cmp_to_key(universal_cmp))
 		for (k, v), (nk, nv) in zip(itms, nitms):
 			if not deeptypecmp(k, nk):
 				return False
@@ -474,15 +493,15 @@ class Test_deeptypecmp(unittest.TestCase):
 
 	def test_false(self):
 		for i in (([[]], [{}]), ([1], ['str']), ([], set()),
-		    ({1: 2, 5: u'sdlkfj'}, {1: 2, 5: 'sdlkfj'}),
-		    ({1: 2, u'sdlkfj': 5}, {1: 2, 'sdlkfj': 5}),
+		    ({1: 2, 5: 'sdlkfj'}, {1: 2, 5: b'sdlkfj'}),
+		    ({1: 2, 'sdlkfj': 5}, {1: 2, b'sdlkfj': 5}),
 		    ):
-			self.assertFalse(deeptypecmp(*i))
+			self.assertFalse(deeptypecmp(*i), '%s != %s' % (i[0], i[1]))
 
 def genfailures(obj):
 	s = dumps(obj)
-	for i in xrange(len(s)):
-		for j in (chr(x) for x in xrange(256)):
+	for i in range(len(s)):
+		for j in (bytes([x]) for x in range(256)):
 			ts = s[:i] + j + s[i + 1:]
 			if ts == s:
 				continue
@@ -493,24 +512,24 @@ def genfailures(obj):
 			except (ValueError, KeyError, IndexError, TypeError):
 				pass
 			else:	# pragma: no cover
-				raise AssertionError('uncaught modification: %s, byte %d, orig: %02x' % (ts.encode('hex'), i, ord(s[i])))
+				raise AssertionError('uncaught modification: %s, byte %d, orig: %02x' % (ts.encode('hex'), i, s[i]))
 
 class TestCode(unittest.TestCase):
 	def test_primv(self):
-		self.assertEqual(dumps(-257), '0202feff'.decode('hex'))
-		self.assertEqual(dumps(-256), '0202ff00'.decode('hex'))
-		self.assertEqual(dumps(-255), '0202ff01'.decode('hex'))
-		self.assertEqual(dumps(-1), '0201ff'.decode('hex'))
-		self.assertEqual(dumps(5), '020105'.decode('hex'))
-		self.assertEqual(dumps(128), '02020080'.decode('hex'))
-		self.assertEqual(dumps(256), '02020100'.decode('hex'))
+		self.assertEqual(dumps(-257), bytes.fromhex('0202feff'))
+		self.assertEqual(dumps(-256), bytes.fromhex('0202ff00'))
+		self.assertEqual(dumps(-255), bytes.fromhex('0202ff01'))
+		self.assertEqual(dumps(-1), bytes.fromhex('0201ff'))
+		self.assertEqual(dumps(5), bytes.fromhex('020105'))
+		self.assertEqual(dumps(128), bytes.fromhex('02020080'))
+		self.assertEqual(dumps(256), bytes.fromhex('02020100'))
 
-		self.assertEqual(dumps(False), '010100'.decode('hex'))
-		self.assertEqual(dumps(True), '0101ff'.decode('hex'))
+		self.assertEqual(dumps(False), bytes.fromhex('010100'))
+		self.assertEqual(dumps(True), bytes.fromhex('0101ff'))
 
-		self.assertEqual(dumps(None), '0500'.decode('hex'))
+		self.assertEqual(dumps(None), bytes.fromhex('0500'))
 
-		self.assertEqual(dumps(.15625), '090380fb05'.decode('hex'))
+		self.assertEqual(dumps(.15625), bytes.fromhex('090380fb05'))
 
 	def test_fuzzing(self):
 		# Make sure that when a failure is detected here, that it
@@ -539,7 +558,7 @@ class TestCode(unittest.TestCase):
 		    '181632303136303231373136343034372e3035343433367a', #datetime w/ lower z
 		    '181632303136313220383031303933302e3931353133385a', #datetime w/ space
 		    ]:
-			self.assertRaises(ValueError, loads, v.decode('hex'))
+			self.assertRaises(ValueError, loads, bytes.fromhex(v))
 
 	def test_invalid_floats(self):
 		import mock
@@ -548,7 +567,7 @@ class TestCode(unittest.TestCase):
 
 	def test_consume(self):
 		b = dumps(5)
-		self.assertRaises(ValueError, loads, b + '398473',
+		self.assertRaises(ValueError, loads, b + b'398473',
 		    consume=True)
 
 		# XXX - still possible that an internal data member
@@ -565,10 +584,10 @@ class TestCode(unittest.TestCase):
 	def test_cryptoutilasn1(self):
 		'''Test DER sequences generated by Crypto.Util.asn1.'''
 
-		for s, v in [ ('\x02\x03$\x8a\xf9', 2394873),
-		    ('\x05\x00', None),
-		    ('\x02\x03\x00\x96I', 38473),
-		    ('\x04\x81\xc8' + '\x00' * 200, '\x00' * 200),
+		for s, v in [ (b'\x02\x03$\x8a\xf9', 2394873),
+		    (b'\x05\x00', None),
+		    (b'\x02\x03\x00\x96I', 38473),
+		    (b'\x04\x81\xc8' + b'\x00' * 200, b'\x00' * 200),
 		    ]:
 			self.assertEqual(loads(s), v)
 
@@ -595,7 +614,7 @@ class TestCode(unittest.TestCase):
 		    sys.float_info.max, sys.float_info.min,
 		    float('.15625'),
 		    'weoifjwef',
-		    u'\U0001f4a9',
+		    '\U0001f4a9',
 		    [], [ 1,2,3 ],
 		    {}, { 5: 10, 'adfkj': 34 },
 		    set(), set((1,2,3)),
@@ -609,8 +628,8 @@ class TestCode(unittest.TestCase):
 			o = loads(s)
 			self.assertEqual(i, o)
 
-		tobj = { 1: 'dflkj', 5: u'sdlkfj', 'float': 1,
-		    'largeint': 1<<342, 'list': [ 1, 2, u'str', 'str' ] }
+		tobj = { 1: 'dflkj', 5: 'sdlkfj', 'float': 1,
+		    'largeint': 1<<342, 'list': [ 1, 2, 'str', 'str' ] }
 
 		out = dumps(tobj)
 		self.assertEqual(tobj, loads(out))
@@ -641,7 +660,7 @@ class TestCode(unittest.TestCase):
 		self.assertEqual(ac.loads(ac.dumps(o)), v)
 		self.assertRaises(TypeError, ac.dumps, Bar())
 
-		v = u'oiejfd'
+		v = b'oiejfd'
 		o = Baz()
 		o.s = v
 
@@ -652,7 +671,7 @@ class TestCode(unittest.TestCase):
 		self.assertRaises(TypeError, dumps, o)
 
 	def test_loads(self):
-		self.assertRaises(ValueError, loads, '\x00\x02\x00')
+		self.assertRaises(ValueError, loads, b'\x00\x02\x00')
 
 	def test_nodict(self):
 		'''Verify that ASN1Coder does not support dict.'''
diff --git a/requirements.txt b/requirements.txt
index 932a895..451b8c9 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1 +1,2 @@
+coverage
 mock