Drop Python 3.6 support (#543)

The following steps have been taken:

1. Black was updated to latest version. The code has been formatted with
the new version.
2. The pyupgrade utility is installed. This helped to remove all the
code that was needed to support Python < 3.7.

Fix #541.

Co-authored-by: Inada Naoki <songofacandy@gmail.com>

test/test_buffer.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# coding: utf-8
 
 import sys
 import pytest

test/test_case.py

@@ -1,11 +1,10 @@
 #!/usr/bin/env python
-# coding: utf-8
 from msgpack import packb, unpackb
 
 
 def check(length, obj, use_bin_type=True):
     v = packb(obj, use_bin_type=use_bin_type)
-    assert len(v) == length, "%r length should be %r but get %r" % (obj, length, len(v))
+    assert len(v) == length, f"{obj!r} length should be {length!r} but get {len(v)!r}"
     assert unpackb(v, use_list=0, raw=not use_bin_type) == obj
 
 
@@ -120,11 +119,11 @@ def test_match():
         ),
         ({}, b"\x80"),
         (
-            dict([(x, x) for x in range(15)]),
+            {x: x for x in range(15)},
             b"\x8f\x00\x00\x01\x01\x02\x02\x03\x03\x04\x04\x05\x05\x06\x06\x07\x07\x08\x08\t\t\n\n\x0b\x0b\x0c\x0c\r\r\x0e\x0e",
         ),
         (
-            dict([(x, x) for x in range(16)]),
+            {x: x for x in range(16)},
             b"\xde\x00\x10\x00\x00\x01\x01\x02\x02\x03\x03\x04\x04\x05\x05\x06\x06\x07\x07\x08\x08\t\t\n\n\x0b\x0b\x0c\x0c\r\r\x0e\x0e\x0f\x0f",
         ),
     ]

test/test_except.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# coding: utf-8
 
 from pytest import raises
 from msgpack import packb, unpackb, Unpacker, FormatError, StackError, OutOfData

test/test_extension.py

@@ -1,4 +1,3 @@
-from __future__ import print_function
 import array
 import msgpack
 from msgpack import ExtType
@@ -17,9 +16,7 @@ def test_pack_ext_type():
     assert p(b"A" * 16) == b"\xd8\x42" + b"A" * 16  # fixext 16
     assert p(b"ABC") == b"\xc7\x03\x42ABC"  # ext 8
     assert p(b"A" * 0x0123) == b"\xc8\x01\x23\x42" + b"A" * 0x0123  # ext 16
-    assert (
-        p(b"A" * 0x00012345) == b"\xc9\x00\x01\x23\x45\x42" + b"A" * 0x00012345
-    )  # ext 32
+    assert p(b"A" * 0x00012345) == b"\xc9\x00\x01\x23\x45\x42" + b"A" * 0x00012345  # ext 32
 
 
 def test_unpack_ext_type():
@@ -49,7 +46,7 @@ def test_extension_type():
             except AttributeError:
                 data = obj.tostring()
             return ExtType(typecode, data)
-        raise TypeError("Unknown type object %r" % (obj,))
+        raise TypeError(f"Unknown type object {obj!r}")
 
     def ext_hook(code, data):
         print("ext_hook called", code, data)

test/test_format.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# coding: utf-8
 
 from msgpack import unpackb
 
@@ -25,9 +24,7 @@ def testFixRaw():
 
 
 def testFixMap():
-    check(
-        b"\x82\xc2\x81\xc0\xc0\xc3\x81\xc0\x80", {False: {None: None}, True: {None: {}}}
-    )
+    check(b"\x82\xc2\x81\xc0\xc0\xc3\x81\xc0\x80", {False: {None: None}, True: {None: {}}})
 
 
 def testUnsignedInt():

test/test_limits.py

@@ -1,6 +1,4 @@
 #!/usr/bin/env python
-# coding: utf-8
-from __future__ import absolute_import, division, print_function, unicode_literals
 import pytest
 
 from msgpack import (

test/test_memoryview.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# coding: utf-8
 
 import pytest
 from array import array

test/test_newspec.py

@@ -1,5 +1,3 @@
-# coding: utf-8
-
 from msgpack import packb, unpackb, ExtType
 
 

test/test_obj.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# coding: utf-8
 
 from pytest import raises
 from msgpack import packb, unpackb

test/test_pack.py

@@ -1,6 +1,4 @@
 #!/usr/bin/env python
-# coding: utf-8
-from __future__ import absolute_import, division, print_function, unicode_literals
 
 from collections import OrderedDict
 from io import BytesIO
@@ -81,9 +79,7 @@ def testPackByteArrays():
 
 
 def testIgnoreUnicodeErrors():
-    re = unpackb(
-        packb(b"abc\xeddef", use_bin_type=False), raw=False, unicode_errors="ignore"
-    )
+    re = unpackb(packb(b"abc\xeddef", use_bin_type=False), raw=False, unicode_errors="ignore")
     assert re == "abcdef"
 
 
@@ -108,8 +104,8 @@ def testDecodeBinary():
 
 
 def testPackFloat():
-    assert packb(1.0, use_single_float=True) == b"\xca" + struct.pack(str(">f"), 1.0)
-    assert packb(1.0, use_single_float=False) == b"\xcb" + struct.pack(str(">d"), 1.0)
+    assert packb(1.0, use_single_float=True) == b"\xca" + struct.pack(">f", 1.0)
+    assert packb(1.0, use_single_float=False) == b"\xcb" + struct.pack(">d", 1.0)
 
 
 def testArraySize(sizes=[0, 5, 50, 1000]):
@@ -154,7 +150,7 @@ def testMapSize(sizes=[0, 5, 50, 1000]):
     bio.seek(0)
     unpacker = Unpacker(bio, strict_map_key=False)
     for size in sizes:
-        assert unpacker.unpack() == dict((i, i * 2) for i in range(size))
+        assert unpacker.unpack() == {i: i * 2 for i in range(size)}
 
 
 def test_odict():

test/test_seq.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# coding: utf-8
 
 import io
 import msgpack

test/test_sequnpack.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# coding: utf-8
 import io
 from msgpack import Unpacker, BufferFull
 from msgpack import pack, packb

test/test_stricttype.py

@@ -1,5 +1,3 @@
-# coding: utf-8
-
 from collections import namedtuple
 from msgpack import packb, unpackb, ExtType
 
@@ -10,7 +8,7 @@ def test_namedtuple():
     def default(o):
         if isinstance(o, T):
             return dict(o._asdict())
-        raise TypeError("Unsupported type %s" % (type(o),))
+        raise TypeError(f"Unsupported type {type(o)}")
 
     packed = packb(T(1, 42), strict_types=True, use_bin_type=True, default=default)
     unpacked = unpackb(packed, raw=False)
@@ -23,7 +21,7 @@ def test_tuple():
     def default(o):
         if isinstance(o, tuple):
             return {"__type__": "tuple", "value": list(o)}
-        raise TypeError("Unsupported type %s" % (type(o),))
+        raise TypeError(f"Unsupported type {type(o)}")
 
     def convert(o):
         if o.get("__type__") == "tuple":
@@ -44,9 +42,7 @@ def test_tuple_ext():
     def default(o):
         if isinstance(o, tuple):
             # Convert to list and pack
-            payload = packb(
-                list(o), strict_types=True, use_bin_type=True, default=default
-            )
+            payload = packb(list(o), strict_types=True, use_bin_type=True, default=default)
             return ExtType(MSGPACK_EXT_TYPE_TUPLE, payload)
         raise TypeError(repr(o))
 
@@ -54,7 +50,7 @@ def test_tuple_ext():
         if code == MSGPACK_EXT_TYPE_TUPLE:
             # Unpack and convert to tuple
             return tuple(unpackb(payload, raw=False, ext_hook=convert))
-        raise ValueError("Unknown Ext code {}".format(code))
+        raise ValueError(f"Unknown Ext code {code}")
 
     data = packb(t, strict_types=True, use_bin_type=True, default=default)
     expected = unpackb(data, raw=False, ext_hook=convert)

test/test_subtype.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python
-# coding: utf-8
 
 from msgpack import packb, unpackb
 from collections import namedtuple

test/test_unpack.py

@@ -52,7 +52,7 @@ def test_unpacker_hook_refcnt():
 def test_unpacker_ext_hook():
     class MyUnpacker(Unpacker):
         def __init__(self):
-            super(MyUnpacker, self).__init__(ext_hook=self._hook, raw=False)
+            super().__init__(ext_hook=self._hook, raw=False)
 
         def _hook(self, code, data):
             if code == 1: