better deal with importing conftest.py with --doctest-modules and

re-enable default of "--doctest-modules" even if issued at root level

_pytest/doctest.py

@@ -73,7 +73,10 @@ class DoctestTextfile(DoctestItem, pytest.File):
 class DoctestModule(DoctestItem, pytest.File):
     def runtest(self):
         doctest = py.std.doctest
-        module = self.fspath.pyimport()
+        if self.fspath.basename == "conftest.py":
+            module = self.config._conftest.importconftest(self.fspath)
+        else:
+            module = self.fspath.pyimport()
         failed, tot = doctest.testmod(
             module, raise_on_error=True, verbose=0,
             optionflags=doctest.ELLIPSIS)

tox.ini

@@ -18,6 +18,7 @@ commands= py.test --genscript=pytest1
 deps=pylib
 
 [testenv:py27-xdist]
+changedir=.
 basepython=python2.7
 deps=pytest-xdist
 commands=
@@ -63,6 +64,6 @@ commands=
 [pytest]
 minversion=2.0
 plugins=pytester
-addopts= -rxf --pyargs
+addopts= -rxf --pyargs --doctest-modules
 rsyncdirs=tox.ini pytest.py _pytest testing