code from ~/src/sage/.
Newer versions of Sage don't load ~/.sage/init.sage during test mode,
-so the imports in mjo/all.py will fail by default. However, as long as
-the other modules don't rely on all.py, their tests should be fine.
+and "packages" need to be imported explicitly. Therefore the test
+suite is a little tricky to run; but "make check" should work.
[1] http://www.sagemath.org/