make sure datetime strings end in Z when decoding..

move some code close and add a comment to the fuzzing test that
detected failures should be added to test_invalids..

[git-p4: depot-paths = "//depot/python/pypasn1/main/": change = 1828]

pasn1.py

@@ -354,6 +354,9 @@ class ASN1Coder(object):
 
 	def dec_datetime(self, data, pos, end):
 		ts = data[pos:end]
+		if ts[-1] != 'Z':
+			raise ValueError('last character must be Z')
+
 		if '.' in ts:
 			fstr = '%Y%m%d%H%M%S.%fZ'
 			if ts.endswith('0Z'):
@@ -457,25 +460,15 @@ class TestCode(unittest.TestCase):
 		self.assertEqual(dumps(.15625), '090380fb05'.decode('hex'))
 
 	def test_fuzzing(self):
+		# Make sure that when a failure is detected here, that it
+		# gets added to test_invalids, so that this function may be
+		# disabled.
 		genfailures(float(1))
 		genfailures([ 1, 2, 'sdlkfj' ])
 		genfailures({ 1: 2, 5: 'sdlkfj' })
 		genfailures(set([ 1, 2, 'sdlkfj' ]))
-
-	def test_consume(self):
-		b = dumps(5)
-		self.assertRaises(ValueError, loads, b + '398473', consume=True)
-
-		# XXX - still possible that an internal data member
-		# doesn't consume all
-
-	# XXX - test that sets are ordered properly
-	# XXX - test that dicts are ordered properly..
-
-	def test_nan(self):
-		s = dumps(float('nan'))
-		v = loads(s)
-		self.assertTrue(math.isnan(v))
+		genfailures(True)
+		genfailures(datetime.datetime.utcnow())
 
 	def test_invalids(self):
 		# Add tests for base 8, 16 floats among others
@@ -489,9 +482,25 @@ class TestCode(unittest.TestCase):
 		    '3007020101020102040673646c6b666a',	# list short string still valid
 		    'c007020101020102020105040673646c6b666a', # dict short value still valid
 		    '181632303136303231353038343031362e3539303839305a', #datetime w/ trailing zero
+		    '181632303136303231373136343034372e3035343433367a', #datetime w/ lower z
 		    ]:
 			self.assertRaises(ValueError, loads, v.decode('hex'))
 
+	def test_consume(self):
+		b = dumps(5)
+		self.assertRaises(ValueError, loads, b + '398473', consume=True)
+
+		# XXX - still possible that an internal data member
+		# doesn't consume all
+
+	# XXX - test that sets are ordered properly
+	# XXX - test that dicts are ordered properly..
+
+	def test_nan(self):
+		s = dumps(float('nan'))
+		v = loads(s)
+		self.assertTrue(math.isnan(v))
+
 	def test_cryptoutilasn1(self):
 		'''Test DER sequences generated by Crypto.Util.asn1.'''