doc: Start improving our pytest documentation

Begin the work of documenting all of our pytests. To do this, we should
have a directory under develop for it as there will be a large number of
new files. As the current document is referenced externally in a number
of locations, add the sphinx_reredirects module so that we can redirect
from the old location to the new.

Signed-off-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

doc/develop/testing.rst

@@ -33,7 +33,7 @@ You can also run a selection tests in parallel with::
     make pcheck
 
 All of the above use the test/run script with a paremeter to select which tests
-are run. See :doc:`py_testing` for more information.
+are run. See :doc:`pytest/usage` for more information.
 
 
 Sandbox
@@ -69,7 +69,7 @@ build::
 
    ./test/py/test.py --bd sandbox_spl --build -k test_spl
 
-See :doc:`py_testing` for more information about the pytest suite.
+See :doc:`pytest/usage` for more information about the pytest suite.
 
 See :doc:`tests_sandbox` for how to run tests directly (not through pytest).