From f36d95f193f3414e13a86960bcb32320f63277e5 Mon Sep 17 00:00:00 2001
From: mcleanmds <michael@mcode.com.au>
Date: Tue, 14 Jul 2020 15:20:49 +1000
Subject: [PATCH 1/2] add parallel testing example to README

---
 README.rst | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)

diff --git a/README.rst b/README.rst
index 0b5a2bf6..64b58712 100644
--- a/README.rst
+++ b/README.rst
@@ -149,6 +149,62 @@ following lines to your test class:
     def tearDown(self):
         get_redis_connection("default").flushall()
 
+In case you want to run the django tests in parallel mode, setup a custom
+TestRunner similar to the following:
+
+.. code-block:: python
+
+    import copy
+    import django.core.cache
+    from django.conf import UserSettingsHolder, settings
+    from django.test.runner import _init_worker
+    from django.test.runner import DiscoverRunner
+    from django.test.runner import ParallelTestSuite
+
+    def parallel_init_worker(counter):
+        """
+        Switch redis database dedicated to this worker.
+
+        This helper lives at module-level because of the multiprocessing module's
+        requirements.
+        """
+        _init_worker(counter)  # call django default parallel init first
+
+        with counter.get_lock():
+            redis_db = settings.CACHE_DB + counter.value
+            redis_location = "redis://127.0.0.1:6379/{}".format(redis_db)
+
+        caches = copy.deepcopy(settings.CACHES)
+        caches["default"]["LOCATION"] = redis_location
+
+        # override the settings for the worker to use
+        override = UserSettingsHolder(settings._wrapped)
+        setattr(override, "CACHES", caches)
+        settings._wrapped = override
+
+        # re-initialise django cache to use new settings
+        django.core.cache.caches = django.core.cache.CacheHandler()
+
+
+    class CustomParallelTestSuite(ParallelTestSuite):
+        init_worker = parallel_init_worker
+
+
+    class CustomDiscoverRunner(DiscoverRunner):
+        parallel_test_suite = CustomParallelTestSuite
+
+When running django tests in parallel mode, flushing the data following a test
+should be limited to the cache db used in that test process, by using
+``flushdb()`` instead of ``flushall()`` in the test class tearDown:
+
+.. code-block:: python
+
+    from django_redis import get_redis_connection
+
+    def tearDown(self):
+        get_redis_connection("default").flushdb()
+
+
 Advanced usage
 --------------
 

From 33deab4b7efcac1b622e25a2d5c6fb6d31a3626a Mon Sep 17 00:00:00 2001
From: Michael McLean <michael@mcode.com.au>
Date: Mon, 27 Nov 2023 14:02:41 +1100
Subject: [PATCH 2/2] Update README.rst

update parallel test suite example config for Django 4.2
---
 README.rst | 30 ++++++++++++++++++++----------
 1 file changed, 20 insertions(+), 10 deletions(-)

diff --git a/README.rst b/README.rst
index 64b58712..2e893afc 100644
--- a/README.rst
+++ b/README.rst
@@ -155,35 +155,44 @@ TestRunner similar to the following:
 .. code-block:: python
 
     import copy
+    import multiprocessing
     import django.core.cache
     from django.conf import UserSettingsHolder, settings
     from django.test.runner import _init_worker
     from django.test.runner import DiscoverRunner
     from django.test.runner import ParallelTestSuite
 
-    def parallel_init_worker(counter):
+    def parallel_init_worker(
+        counter: multiprocessing.Value,
+        *args, **kwargs,
+    ):
         """
         Switch redis database dedicated to this worker.
 
         This helper lives at module-level because of the multiprocessing module's
         requirements.
         """
-        _init_worker(counter)  # call django default parallel init first
+        
+        _init_worker(counter, *args, **kwargs)  # call django default to setup parallel db
+        from django.test.runner import _worker_id  # import after _init_worker called
 
-        with counter.get_lock():
-            redis_db = settings.CACHE_DB + counter.value
-            redis_location = "redis://127.0.0.1:6379/{}".format(redis_db)
+        redis_db = settings.CACHE_DB + _worker_id
+        redis_test_location = f'redis://127.0.0.1:6379/{redis_db}'
 
         caches = copy.deepcopy(settings.CACHES)
         caches["default"]["LOCATION"] = redis_location
 
-        # override the settings for the worker to use
+        # based of approach in django.tests.utils.override_settings
         override = UserSettingsHolder(settings._wrapped)
-        setattr(override, "CACHES", caches)
+        setattr(override, 'CACHE_DB', redis_db)
+        setattr(override, 'REDIS_SERVER_LOCATION', redis_test_location)
+        setattr(override, 'CACHES', caches)
         settings._wrapped = override
-
-        # re-initialise django cache to use new settings
-        django.core.cache.caches = django.core.cache.CacheHandler()
+    
+        setting_changed.send(
+            sender=settings._wrapped.__class__,
+            setting='CACHES', value=caches, enter=True,
+        )
 
 
     class CustomParallelTestSuite(ParallelTestSuite):
@@ -193,6 +202,7 @@ TestRunner similar to the following:
     class CustomDiscoverRunner(DiscoverRunner):
         parallel_test_suite = CustomParallelTestSuite
 
+
 When running django tests in parallel mode, flushing the data following a test
 should be limited to the cache db used in that test process, by using
 ``flushdb()`` instead of ``flushall()`` in the test class tearDown: