Use subTest, move to test_stftime_special

Author: StanFromIreland

Lib/test/datetimetester.py

@@ -4084,13 +4084,6 @@ def test_strftime(self):
         # A naive object replaces %z, %:z and %Z with empty strings.
         self.assertEqual(t.strftime("'%z' '%:z' '%Z'"), "'' '' ''")
 
-        # gh-152305: the year directives must not raise on a time (1900-01-01).
-        t1230 = self.theclass(12, 30)
-        self.assertEqual(t1230.strftime('%Y'), '1900')
-        self.assertEqual(t1230.strftime('%G'), '1900')
-        self.assertEqual(t1230.strftime('%C'), '19')
-        self.assertEqual(t1230.strftime('%F'), '1900-01-01')
-
         # bpo-34482: Check that surrogates don't cause a crash.
         try:
             t.strftime('%H\ud800%M')
@@ -4126,6 +4119,11 @@ def test_strftime_special(self):
         self.assertEqual(t.strftime('\0'*1000), '\0'*1000)
         self.assertEqual(t.strftime('\0%I%p%Z\0%X'), f'\0{s1}\0{s2}')
         self.assertEqual(t.strftime('%I%p%Z\0%X\0'), f'{s1}\0{s2}\0')
+        # gh-152305: the year directives must not raise on a time.
+        for directive, expected in (('%Y', '1900'), ('%G', '1900'),
+                                    ('%C', '19'), ('%F', '1900-01-01')):
+            with self.subTest(directive=directive):
+                self.assertEqual(t.strftime(directive), expected)
 
     def test_format(self):
         t = self.theclass(1, 2, 3, 4)