fix: tests under Python 3.13 (fixes #228)

docs/index.rst

@@ -4,7 +4,7 @@ Dependencies
 ------------
 
 The `argh` library is supported (and tested unless otherwise specified)
-on the following versions of Python: 3.8, 3.9, 3.10, 3.11, 3.12.
+on the following versions of Python: 3.8, 3.9, 3.10, 3.11, 3.12, .13.
 
 If you need support for ancient Pythons, please use the following versions
 of Argh (the numeric puns were semi-intentional):

pyproject.toml

@@ -36,6 +36,7 @@ classifiers  = [
   "Programming Language :: Python :: 3.10",
   "Programming Language :: Python :: 3.11",
   "Programming Language :: Python :: 3.12",
+  "Programming Language :: Python :: 3.13",
   "Programming Language :: Python :: Implementation :: CPython",
   "Programming Language :: Python :: Implementation :: PyPy",
   "Topic :: Software Development :: User Interfaces",

tests/test_integration.py

@@ -724,18 +724,34 @@ def remind(
     help_normalised = re.sub(r"\s+", " ", parser.format_help())
 
     assert "name 'Basil'" in help_normalised
-    assert "-t TASK, --task TASK 'hang the Moose'" in help_normalised
-    assert (
-        "-r REASON, --reason REASON 'there are creatures living in it'"
-        in help_normalised
-    )
 
-    # explicit help message is not obscured by the implicit one
-    # but is still present
-    assert (
-        "-n NOTE, --note NOTE why is it a remarkable animal? "
-        "(default: 'it can speak English')"
-    ) in help_normalised
+    # argh#228 — argparse in Python before 3.13 duplicated the placeholder in help
+    if sys.version_info < (3, 13):
+        assert "-t TASK, --task TASK 'hang the Moose'" in help_normalised
+        assert (
+            "-r REASON, --reason REASON 'there are creatures living in it'"
+            in help_normalised
+        )
+
+        # explicit help message is not obscured by the implicit one
+        # but is still present
+        assert (
+            "-n NOTE, --note NOTE why is it a remarkable animal? "
+            "(default: 'it can speak English')"
+        ) in help_normalised
+    else:
+        assert "-t, --task TASK 'hang the Moose'" in help_normalised
+        assert (
+            "-r, --reason REASON 'there are creatures living in it'"
+            in help_normalised
+        )
+
+        # explicit help message is not obscured by the implicit one
+        # but is still present
+        assert (
+            "-n, --note NOTE why is it a remarkable animal? "
+            "(default: 'it can speak English')"
+        ) in help_normalised
 
 
 def test_default_arg_values_in_help__regression():
@@ -750,9 +766,16 @@ def foo(*, bar=""):
     # doesn't break
     parser.format_help()
 
+    # argh#228 — argparse in Python before 3.13 duplicated the placeholder in help
+    if sys.version_info < (3, 13):
+        expected_line = "-b BAR, --bar BAR  ''"
+        # note the empty str repr         ^^^
+    else:
+        expected_line = "-b, --bar BAR  ''"
+        # note the empty str repr     ^^^
+
     # now check details
-    assert "-b BAR, --bar BAR  ''" in parser.format_help()
-    # note the empty str repr ^^^
+    assert expected_line in parser.format_help()
 
 
 def test_help_formatting_is_preserved():
@@ -868,6 +891,19 @@ def second_func():
 
     run(parser, "first-func --help", exit=True)
     captured = capsys.readouterr()
+
+    # argh#228 — argparse in Python before 3.13 duplicated the placeholder in help
+    if sys.version_info < (3, 13):
+        arg_help_lines = (
+            "  -h, --help         show this help message and exit\n"
+            "  -f FOO, --foo FOO  123"
+        )
+    else:
+        arg_help_lines = (
+            "  -h, --help     show this help message and exit\n"
+            "  -f, --foo FOO  123"
+        )
+
     assert (
         captured.out
         == unindent(
@@ -877,8 +913,7 @@ def second_func():
         Owl stretching time
 
         {HELP_OPTIONS_LABEL}:
-          -h, --help         show this help message and exit
-          -f FOO, --foo FOO  123
+        {arg_help_lines}
         """
         )[1:]
     )
@@ -997,6 +1032,19 @@ def second_func():
 
     run(parser, "my-group first-func --help", exit=True)
     captured = capsys.readouterr()
+
+    # argh#228 — argparse in Python before 3.13 duplicated the placeholder in help
+    if sys.version_info < (3, 13):
+        arg_help_lines = (
+            "  -h, --help         show this help message and exit\n"
+            "  -f FOO, --foo FOO  123"
+        )
+    else:
+        arg_help_lines = (
+            "  -h, --help     show this help message and exit\n"
+            "  -f, --foo FOO  123"
+        )
+
     assert (
         captured.out
         == unindent(
@@ -1006,8 +1054,7 @@ def second_func():
         Owl stretching time
 
         {HELP_OPTIONS_LABEL}:
-          -h, --help         show this help message and exit
-          -f FOO, --foo FOO  123
+        {arg_help_lines}
         """
         )[1:]
     )
@@ -1079,6 +1126,19 @@ def second_func():
 
     run(parser, "first-func --help", exit=True)
     captured = capsys.readouterr()
+
+    # argh#228 — argparse in Python before 3.13 duplicated the placeholder in help
+    if sys.version_info < (3, 13):
+        arg_help_lines = (
+            "  -h, --help         show this help message and exit\n"
+            "  -f FOO, --foo FOO  123"
+        )
+    else:
+        arg_help_lines = (
+            "  -h, --help     show this help message and exit\n"
+            "  -f, --foo FOO  123"
+        )
+
     assert (
         captured.out
         == unindent(
@@ -1088,8 +1148,7 @@ def second_func():
         func description override
 
         {HELP_OPTIONS_LABEL}:
-          -h, --help         show this help message and exit
-          -f FOO, --foo FOO  123
+        {arg_help_lines}
         """
         )[1:]
     )

tox.ini

@@ -5,6 +5,7 @@ envlist =
     py310
     py311
     py312
+    py313
     pypy3
     as-module
     lint
@@ -21,6 +22,7 @@ python =
     3.10: py310
     3.11: py311,lint,as-module
     3.12: py312
+    3.13: py313
     pypy-3.9: pypy3
     pypy-3.10: pypy3