Fixed #23742 -- Added an option to reverse tests order.

This is useful for debugging side effects affecting tests that
are usually executed before a given test. Full suite and pair
tests sort cases more or less deterministically, thus some test
cross-dependencies are easier to reveal by reversing the order.

Thanks Preston Timmons for the review.

1 files changed, 12 insertions, 0 deletions

diff --git a/docs/internals/contributing/writing-code/unit-tests.txt b/docs/internals/contributing/writing-code/unit-tests.txt
index 286fd36f9c..2497c5e65a 100644
--- a/docs/internals/contributing/writing-code/unit-tests.txt
+++ b/docs/internals/contributing/writing-code/unit-tests.txt
@@ -307,3 +307,15 @@ the first one:
 .. code-block:: bash
 
    $ ./runtests.py --pair basic.tests.ModelTest.test_eq queries transactions
+
+You can also try running any set of tests in reverse using the ``--reverse``
+option in order to verify that executing tests in a different order does not
+cause any trouble:
+
+.. code-block:: bash
+
+   $ ./runtests.py basic --reverse
+
+.. versionadded:: 1.8
+
+    The ``--reverse`` option was added.