Merge sagemath#32614

Author: mkoeppe

src/sage/doctest/control.py

@@ -53,6 +53,9 @@
 except ImportError:
     pass
 
+from sage.features.sagemath import sage_optional_tags
+auto_optional_tags.update(sage_optional_tags())
+
 class DocTestDefaults(SageObject):
     """
     This class is used for doctesting the Sage doctest module.

src/sage/doctest/parsing.py

@@ -34,7 +34,7 @@
 from .external import available_software
 
 float_regex = re.compile(r'\s*([+-]?\s*((\d*\.?\d+)|(\d+\.?))([eE][+-]?\d+)?)')
-optional_regex = re.compile(r'(arb216|arb218|py2|py3|long time|not implemented|not tested|known bug)|([^ a-z]\s*optional\s*[:-]*((\s|\w)*))')
+optional_regex = re.compile(r'(arb216|arb218|py2|py3|long time|not implemented|not tested|known bug)|([^ a-z]\s*optional\s*[:-]*((\s|\w|[.])*))')
 # Version 4.65 of glpk prints the warning "Long-step dual simplex will
 # be used" frequently. When Sage uses a system installation of glpk
 # which has not been patched, we need to ignore that message.
@@ -316,6 +316,8 @@ def parse_optional_tags(string):
         {''}
         sage: sorted(list(parse_optional_tags("sage: #optional -- foo bar, baz")))
         ['bar', 'foo']
+        sage: parse_optional_tags("sage: #optional -- foo.bar, baz")
+        {'foo.bar'}
         sage: sorted(list(parse_optional_tags("    sage: factor(10^(10^10) + 1) # LoNg TiME, NoT TeSTED; OptioNAL -- P4cka9e")))
         ['long time', 'not tested', 'p4cka9e']
         sage: parse_optional_tags("    sage: raise RuntimeError # known bug")

src/sage/features/sagemath.py

@@ -0,0 +1,56 @@
+r"""
+Check for SageMath Python modules
+"""
+from . import PythonModule
+
+
+class sage__combinat(PythonModule):
+
+    def __init__(self):
+        # sage.combinat will be a namespace package.
+        # Testing whether sage.combinat itself can be imported is meaningless.
+        # Hence, we test a Python module within the package.
+        PythonModule.__init__(self, 'sage.combinat.combinations')
+
+
+class sage__graphs(PythonModule):
+
+    def __init__(self):
+        PythonModule.__init__(self, 'sage.graphs.graph')
+
+
+class sage__rings__real_double(PythonModule):
+
+    def __init__(self):
+        PythonModule.__init__(self, 'sage.rings.real_double')
+
+
+class sage__symbolic(PythonModule):
+
+    def __init__(self):
+        PythonModule.__init__(self, 'sage.symbolic.expression', spkg="sagemath_symbolics")
+
+
+def sage_optional_tags():
+    """
+    Return tags for conditionalizing doctests.
+
+    These tags are named after Python packages/modules (e.g., :mod:`~sage.symbolic`),
+    not distribution packages (``sagemath-symbolics``).
+
+    This is motivated by a separation of concerns: The author of a module that depends
+    on some functionality provided by a Python module usually already knows the
+    name of the Python module, so we do not want to force the author to also
+    know about the distribution package that provides the Python module.
+
+    Instead, we associate distribution packages to Python modules in
+    :mod:`sage.features.sagemath` via the ``spkg`` parameter of :class:`PythonModule``.
+    """
+    if sage__combinat().is_present():
+        yield 'sage.combinat'
+    if sage__graphs().is_present():
+        yield 'sage.graphs'
+    if sage__rings__real_double().is_present():
+        yield 'sage.rings.real_double'
+    if sage__symbolic().is_present():
+        yield 'sage.symbolic'