Update tests: for forbidden 'z' usage

Forbid '', 'd', and 'n' presentation types from using two's complements
as per formatter_unicode::format_long_internal

Author: jb2170

Lib/test/test_format.py

@@ -775,9 +775,19 @@ def test_specifier_z_error(self):
         with self.assertRaisesRegex(ValueError, error_msg):
             f"{0:fz}"  # wrong position
 
-        error_msg = re.escape("Negative zero coercion (z) not allowed")
+        error_msg = re.escape("Two's complement (z) requires precision (.) format specifier")
+        with self.assertRaisesRegex(ValueError, error_msg):
+            f"{0:zx}"  # can't apply two's complement without precision
+
+        error_msg = re.escape("Two's complement (z) only allowed with integer presentation types 'b', 'o', 'x', and 'X'")
+        with self.assertRaisesRegex(ValueError, error_msg):
+            f"{0:z.8}"  # can't apply to '' int presentation type
         with self.assertRaisesRegex(ValueError, error_msg):
-            f"{0:zd}"  # can't apply to int presentation type
+            f"{0:z.8d}"  # can't apply to 'd' int presentation type
+        with self.assertRaisesRegex(ValueError, error_msg):
+            f"{0:z.8n}"  # can't apply to 'n' int presentation type
+
+        error_msg = re.escape("Negative zero coercion (z) not allowed")
         with self.assertRaisesRegex(ValueError, error_msg):
             f"{'x':zs}"  # can't apply to string