BUG: collect methods from private superclasses

scipy_doctest/frontend.py

@@ -97,6 +97,14 @@ def find_doctests(module, strategy=None,
             t = _finder.find(item, name, globs=globs, extraglobs=extraglobs)
         else:
             t = finder.find(item, full_name, globs=globs, extraglobs=extraglobs)
+
+            if hasattr(item, '__mro__'):
+                # is a class, inspect superclasses
+                # cf https://github.com/scipy/scipy_doctest/issues/177
+                # item.__mro__ starts with itself, ends with `object`
+                for item_ in item.__mro__[1:-1]:
+                    t_ = finder.find(item_, full_name, globs=globs, extraglobs=extraglobs)
+                    t += t_
         tests += t
 
     # If the skiplist contains methods of objects, their doctests may have been

scipy_doctest/tests/finder_cases_2.py

@@ -0,0 +1,22 @@
+"""
+Private method in subclasses
+"""
+
+__all__ = ["Klass"]
+
+class _PrivateKlass:
+    def private_method(self):
+        """
+        >>> 2 / 3
+        0.667
+        """
+        pass
+
+
+class Klass(_PrivateKlass):
+    def public_method(self):
+        """
+        >>> 3 / 4
+        0.74
+        """
+        pass

scipy_doctest/tests/test_finder.py

@@ -1,6 +1,7 @@
 import pytest
 
 from . import finder_cases
+from . import finder_cases_2
 from ..util import get_all_list, get_public_objects
 from ..impl import DTFinder, DTConfig
 from ..frontend import find_doctests
@@ -168,3 +169,14 @@ def test_dtfinder_config():
     config = DTConfig()
     finder = DTFinder(config=config)
     assert finder.config is config
+
+
+@pytest.mark.parametrize('strategy', [None, 'api'])
+def test_private_superclasses(strategy):
+    # Test that methods from inherited private superclasses get collected
+    tests = find_doctests(finder_cases_2, strategy=strategy)
+
+    names = set(test.name.split('.')[-1] for test in tests)
+    assert len(tests) == 3
+    assert names == {'finder_cases_2', 'public_method', 'private_method'}
+