[CI] run fasttest with pypy

use pypy3 as py39 base python because the current pypy3
bases on Python 3.9. This ensures that fasttest-py39 runs
with pypy.

Fix gui_tests because pypy3 has a tkinter module but this just
raises ImportError if _tkinter is not installed; require_modules
does not work here for tkinter.

Change-Id: I2640dd17f62d5d40b54d8e5cf1279661d094e302

tests/gui_tests.py

@@ -55,7 +55,7 @@ def test_tkinter(self):
         self.assertIn('Main Page', text)
 
 
-@require_modules('tkinter', 'PIL')
+@require_modules('PIL')
 def setUpModule():
     """Skip tests if tkinter or PIL is not installed.
 
@@ -67,7 +67,13 @@ def setUpModule():
                                 '(set PYWIKIBOT_TEST_GUI=1 to enable)')
 
     global EditBoxWindow, Tkdialog, tkinter
-    import tkinter
+
+    # pypy3 has a tkinter module which just raises importError if _tkinter
+    # is not installed; thus require_modules does not work for it.
+    try:
+        import tkinter
+    except ImportError as e:
+        raise unittest.SkipTest(e)
 
     from pywikibot.userinterfaces.gui import EditBoxWindow, Tkdialog
 

tox.ini

@@ -5,19 +5,20 @@ skipsdist = True
 skip_missing_interpreters = True
 envlist =
     commit-message
-    flake8-py{37,312,py}
-    hacking-py{37,312,py}
+    flake8-py3{7,9,12}
+    hacking-py3{7,9,12}
 
 [params]
 # Note: tox 4 does not support multiple lines when doing parameters
 # substitution.
 generate_user_files = -W error::UserWarning -m pwb generate_user_files -family:wikipedia -lang:test -v
 
 [testenv]
+# pypy3 bases on Python 3.9
 basepython =
     py37: python3.7
     py38: python3.8
-    py39: python3.9
+    py39: pypy3
     py310: python3.10
     py311: python3.11
     py312: python3.12