diff -r 873d0fecb9a3 -r de7838053207 contrib/python-zstandard/tests/test_train_dictionary.py
--- a/contrib/python-zstandard/tests/test_train_dictionary.py	Fri Dec 27 18:54:57 2019 -0500
+++ b/contrib/python-zstandard/tests/test_train_dictionary.py	Sat Dec 28 09:55:45 2019 -0800
@@ -4,10 +4,11 @@
 
 import zstandard as zstd
 
-from . common import (
+from .common import (
     generate_samples,
     make_cffi,
     random_input_data,
+    TestCase,
 )
 
 if sys.version_info[0] >= 3:
@@ -17,24 +18,24 @@
 
 
 @make_cffi
-class TestTrainDictionary(unittest.TestCase):
+class TestTrainDictionary(TestCase):
     def test_no_args(self):
         with self.assertRaises(TypeError):
             zstd.train_dictionary()
 
     def test_bad_args(self):
         with self.assertRaises(TypeError):
-            zstd.train_dictionary(8192, u'foo')
+            zstd.train_dictionary(8192, u"foo")
 
         with self.assertRaises(ValueError):
-            zstd.train_dictionary(8192, [u'foo'])
+            zstd.train_dictionary(8192, [u"foo"])
 
     def test_no_params(self):
         d = zstd.train_dictionary(8192, random_input_data())
         self.assertIsInstance(d.dict_id(), int_type)
 
         # The dictionary ID may be different across platforms.
-        expected = b'\x37\xa4\x30\xec' + struct.pack('<I', d.dict_id())
+        expected = b"\x37\xa4\x30\xec" + struct.pack("<I", d.dict_id())
 
         data = d.as_bytes()
         self.assertEqual(data[0:8], expected)
@@ -44,46 +45,48 @@
         self.assertIsInstance(d.dict_id(), int_type)
 
         data = d.as_bytes()
-        self.assertEqual(data[0:4], b'\x37\xa4\x30\xec')
+        self.assertEqual(data[0:4], b"\x37\xa4\x30\xec")
 
         self.assertEqual(d.k, 64)
         self.assertEqual(d.d, 16)
 
     def test_set_dict_id(self):
-        d = zstd.train_dictionary(8192, generate_samples(), k=64, d=16,
-                                  dict_id=42)
+        d = zstd.train_dictionary(8192, generate_samples(), k=64, d=16, dict_id=42)
         self.assertEqual(d.dict_id(), 42)
 
     def test_optimize(self):
-        d = zstd.train_dictionary(8192, generate_samples(), threads=-1, steps=1,
-                                  d=16)
+        d = zstd.train_dictionary(8192, generate_samples(), threads=-1, steps=1, d=16)
 
         # This varies by platform.
         self.assertIn(d.k, (50, 2000))
         self.assertEqual(d.d, 16)
 
+
 @make_cffi
-class TestCompressionDict(unittest.TestCase):
+class TestCompressionDict(TestCase):
     def test_bad_mode(self):
-        with self.assertRaisesRegexp(ValueError, 'invalid dictionary load mode'):
-            zstd.ZstdCompressionDict(b'foo', dict_type=42)
+        with self.assertRaisesRegex(ValueError, "invalid dictionary load mode"):
+            zstd.ZstdCompressionDict(b"foo", dict_type=42)
 
     def test_bad_precompute_compress(self):
         d = zstd.train_dictionary(8192, generate_samples(), k=64, d=16)
 
-        with self.assertRaisesRegexp(ValueError, 'must specify one of level or '):
+        with self.assertRaisesRegex(ValueError, "must specify one of level or "):
             d.precompute_compress()
 
-        with self.assertRaisesRegexp(ValueError, 'must only specify one of level or '):
-            d.precompute_compress(level=3,
-                                  compression_params=zstd.CompressionParameters())
+        with self.assertRaisesRegex(ValueError, "must only specify one of level or "):
+            d.precompute_compress(
+                level=3, compression_params=zstd.CompressionParameters()
+            )
 
     def test_precompute_compress_rawcontent(self):
-        d = zstd.ZstdCompressionDict(b'dictcontent' * 64,
-                                     dict_type=zstd.DICT_TYPE_RAWCONTENT)
+        d = zstd.ZstdCompressionDict(
+            b"dictcontent" * 64, dict_type=zstd.DICT_TYPE_RAWCONTENT
+        )
         d.precompute_compress(level=1)
 
-        d = zstd.ZstdCompressionDict(b'dictcontent' * 64,
-                                     dict_type=zstd.DICT_TYPE_FULLDICT)
-        with self.assertRaisesRegexp(zstd.ZstdError, 'unable to precompute dictionary'):
+        d = zstd.ZstdCompressionDict(
+            b"dictcontent" * 64, dict_type=zstd.DICT_TYPE_FULLDICT
+        )
+        with self.assertRaisesRegex(zstd.ZstdError, "unable to precompute dictionary"):
             d.precompute_compress(level=1)