Support labels with values

Author: serhiy-storchaka

Doc/library/test.rst

@@ -531,13 +531,16 @@ The :mod:`!test.support` module defines the following functions:
    rather than looking directly in the path directories.
 
 
-.. function:: mark(label, *, globals=None)
+.. function:: mark(label, value=True, *, globals=None)
 
    Add a label to tests.
    The ``@mark('label')`` decorator adds a label to method or class.
    ``test.support.mark('label', globals=globals())`` adds a label to the whole
    module.
 
+   The optional *value* (``True`` by default) is matched on the command line
+   by ``--label label=value``, whereas ``--label label`` matches any value.
+
    Many :mod:`test.support` decorators like :func:`requires_resource`,
    :func:`~test.support.cpython_only` or :func:`bigmemtest` add labels
    automatically.

Lib/test/libregrtest/cmdline.py

@@ -300,12 +300,14 @@ def _create_parser():
     group.add_argument('-i', '--ignore', metavar='PAT',
                        dest='match_tests', action=FilterAction, const=False,
                        help='ignore test cases and methods with glob pattern `PAT`')
-    group.add_argument('--label', metavar='NAME',
+    group.add_argument('--label', metavar='NAME[=VALUE]',
                        dest='match_labels', action=FilterAction, const=True,
-                       help='match test cases and methods with label `NAME`')
-    group.add_argument('--no-label', metavar='NAME',
+                       help='match test cases and methods with label `NAME` '
+                            '(optionally only if its value is `VALUE`)')
+    group.add_argument('--no-label', metavar='NAME[=VALUE]',
                        dest='match_labels', action=FilterAction, const=False,
-                       help='ignore test cases and methods with label `NAME`')
+                       help='ignore test cases and methods with label `NAME` '
+                            '(optionally only if its value is `VALUE`)')
     group.add_argument('--matchfile', metavar='FILENAME',
                        dest='match_tests',
                        action=FromFileFilterAction, const=True,

Lib/test/libregrtest/filter.py

@@ -9,6 +9,9 @@
 _test_patterns = ()
 _match_labels = ()
 
+# Sentinel returned by _get_label() when the test has no such label.
+_no_label = object()
+
 
 def match_test(test):
     # Function used by support.run_unittest() and regrtest --list-cases
@@ -23,27 +26,35 @@ def match_test_id(test):
 
 def match_test_label(test):
     result = False
-    for label, result in reversed(_match_labels):
-        if _has_label(test, label):
+    for name, value, result in reversed(_match_labels):
+        actual = _get_label(test, name)
+        if actual is _no_label:
+            continue
+        # value is None for a plain "--label name" (match any value).
+        if value is None or value == str(actual):
             return result
     return not result
 
-def _has_label(test, label):
+def _get_label(test, label):
     attrname = f'_label_{label}'
-    if hasattr(test, attrname):
-        return True
+    value = getattr(test, attrname, _no_label)
+    if value is not _no_label:
+        return value
     testMethod = getattr(test, test._testMethodName)
     while testMethod is not None:
-        if hasattr(testMethod, attrname):
-            return True
+        value = getattr(testMethod, attrname, _no_label)
+        if value is not _no_label:
+            return value
         testMethod = getattr(testMethod, '__wrapped__', None)
     try:
         module = sys.modules[test.__class__.__module__]
-        if hasattr(module, attrname):
-            return True
     except KeyError:
         pass
-    return False
+    else:
+        value = getattr(module, attrname, _no_label)
+        if value is not _no_label:
+            return value
+    return _no_label
 
 
 def _is_full_match_test(pattern):
@@ -80,7 +91,13 @@ def set_match_tests(patterns=None, match_labels=None):
     if not match_labels:
         _match_labels = ()
     else:
-        _match_labels = tuple(match_labels)
+        # "name" matches a label with any value, "name=value" matches only
+        # the specified value.
+        _match_labels = tuple(
+            (name, value if sep else None, result)
+            for label, result in match_labels
+            for name, sep, value in [label.partition('=')]
+        )
 
 
 def _compile_match_function(patterns):

Lib/test/support/__init__.py

@@ -1352,18 +1352,21 @@ def wrapper(self):
 #=======================================================================
 # unittest integration.
 
-def mark(label, *, globals=None):
+def mark(label, value=True, *, globals=None):
     """Add a label to test.
 
     To add a label to method or class, use it as a decorator.
 
     To add a label to module, pass the globals() dict as the globals argument.
+
+    The optional value (``True`` by default) can be matched on the command
+    line with ``--label name=value``.
     """
     if globals is not None:
-        globals[f'_label_{label}'] = True
+        globals[f'_label_{label}'] = value
         return
     def decorator(test):
-        setattr(test, f'_label_{label}', True)
+        setattr(test, f'_label_{label}', value)
         return test
     return decorator
 

Misc/NEWS.d/next/Tests/2023-09-03-12-53-53.gh-issue-108828.zoWIyX.rst

@@ -3,5 +3,7 @@ decorator adds a label to method or class. ``test.support.mark('label',
 globals=globals())`` adds a label to the whole module. Many
 :mod:`test.support` decorators like :func:`~test.support.requires_resource`,
 :func:`~test.support.cpython_only` or :func:`~test.support.bigmemtest` add
-labels automatically.  Tests which have or have not the specified label can
-be filtered by options ``--label`` and ``--no-label``.
+labels automatically.  A label can have a value (``True`` by default).  Tests
+which have or have not the specified label can be filtered by options
+``--label`` and ``--no-label``; ``--label name=value`` matches a specific
+value, while ``--label name`` matches any value.