[IMPR] use dataclasses with make_dist.py; Python 3.7+ required

Change-Id: I1450bc103ac7899436bc3cdbfa53b382dd393004
---
M make_dist.py
M tests/make_dist_tests.py
2 files changed, 27 insertions(+), 9 deletions(-)

diff --git a/make_dist.py b/make_dist.py
index 45d64b7..1fca5b1 100755
--- a/make_dist.py
+++ b/make_dist.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python3
-"""Script to create a new distribution.
+"""Script to create a new distribution. Requires Python 3.7+.
 
 The following options are supported:
 
@@ -37,6 +37,7 @@
    - *nodist* option was added
 
 .. versionchanged:: 8.1
+   Python 3.7+ required because *dataclasses* module is used.
    *nodist* option was removed, *clear* option does not create a
    distribution. *local* and *remote* option clears old distributions
    first.
@@ -49,6 +50,7 @@
 import abc
 import shutil
 import sys
+from dataclasses import dataclass, field
 from pathlib import Path
 from subprocess import check_call, run
 
@@ -57,19 +59,24 @@
 from pywikibot.backports import Tuple
 
 
+@dataclass
 class SetupBase(abc.ABC):
 
     """Setup distribution base class.
 
     .. versionadded:: 8.0
+    .. versionchanged:: 8.1
+       *dataclass* is used.
     """
 
-    def __init__(self, local, remote, clear, upgrade) -> None:
-        """Initializer."""
-        self.local = local
-        self.remote = remote
-        self.clear = clear
-        self.upgrade = upgrade
+    local: bool
+    remote: bool
+    clear: bool
+    upgrade: bool
+    folder: Path = field(init=False)
+
+    def __post_init__(self) -> None:
+        """Post-init initializer."""
         self.folder = Path().resolve()
 
     def clear_old_dist(self) -> None:  # pragma: no cover
diff --git a/tests/make_dist_tests.py b/tests/make_dist_tests.py
index 264e634..1a79759 100755
--- a/tests/make_dist_tests.py
+++ b/tests/make_dist_tests.py
@@ -9,11 +9,11 @@
 import sys
 import unittest
 
-from make_dist import handle_args
 from pywikibot import __version__
-from tests.aspects import TestCase
+from tests.aspects import TestCase, require_modules
 
 
+@require_modules('dataclasses')  # Python 3.7+
 class TestMakeDist(TestCase):
 
     """Test the make_dist script."""
@@ -29,12 +29,14 @@
 
     def test_handle_args_empty(self):
         """Test make_dist handle_args function."""
+        from make_dist import handle_args
         args = handle_args()
         self.assertEqual(args, (False, ) * 4)
         self._test_argv()
 
     def test_handle_args(self):
         """Test make_dist handle_args function."""
+        from make_dist import handle_args
         sys.argv += ['-clear', '-local', '-remote', '-upgrade']
         local, remote, clear, upgrade = handle_args()
         self.assertTrue(local)

