[5.2.x] Moved manual testing instructions from intro to submitting patches docs.

The section on manual testing, including how to use a local checkout of
Django, is moved from the contribution intro to the submitting patches
docs. This makes it easier for reviewers and authors to follow best
practices.

Backport of fdeca380724d523330db9d816c4cda50cda320fd from main.

1 files changed, 19 insertions, 0 deletions

diff --git a/docs/internals/contributing/writing-code/submitting-patches.txt b/docs/internals/contributing/writing-code/submitting-patches.txt
index 5fe3a151de..173c0a56c7 100644
--- a/docs/internals/contributing/writing-code/submitting-patches.txt
+++ b/docs/internals/contributing/writing-code/submitting-patches.txt
@@ -312,6 +312,25 @@ Once you have completed these steps, you are finished with the deprecation.
 In each :term:`feature release <Feature release>`, all
 ``RemovedInDjangoXXWarning``\s matching the new version are removed.
 
+Testing with a Django project
+=============================
+
+It's important to test local changes using a Django project. This allows
+ensuring that the changes behave as expected in a real environment, especially
+for user-facing features such as templates, forms, or the admin.
+
+To do this:
+
+#. Create a virtual environment and :ref:`install the cloned copy of Django in
+   editable mode <intro-contributing-install-local-copy>`.
+
+#. Set up a Django project outside the source tree (you can use the :doc:`first
+   part of the tutorial </intro/tutorial01>` for guidance).
+
+With this setup, any changes made to the Django checkout will take effect
+immediately in the test project, allowing manual testing of contributions
+against a new or existing app.
+
 JavaScript contributions
 ========================