Refs #31055 -- Made DiscoverRunner skip running system checks on unused test databases.

django/test/runner.py

@@ -630,10 +630,10 @@ class DiscoverRunner:
             'buffer': self.buffer,
         }
 
-    def run_checks(self):
+    def run_checks(self, databases):
         # Checks are run after database creation since some checks require
         # database access.
-        call_command('check', verbosity=self.verbosity)
+        call_command('check', verbosity=self.verbosity, databases=databases)
 
     def run_suite(self, suite, **kwargs):
         kwargs = self.get_test_runner_kwargs()
@@ -695,7 +695,7 @@ class DiscoverRunner:
         old_config = self.setup_databases(aliases=databases)
         run_failed = False
         try:
-            self.run_checks()
+            self.run_checks(databases)
             result = self.run_suite(suite)
         except Exception:
             run_failed = True

docs/releases/3.1.txt

@@ -332,6 +332,9 @@ Tests
 * Django test runner now supports a :option:`test --buffer` option to discard
   output for passing tests.
 
+* :class:`~django.test.runner.DiscoverRunner` now skips running the system
+  checks on databases not :ref:`referenced by tests<testing-multi-db>`.
+
 URLs
 ~~~~
 

docs/topics/testing/advanced.txt

@@ -637,9 +637,13 @@ Methods
     Creates the test databases by calling
     :func:`~django.test.utils.setup_databases`.
 
-.. method:: DiscoverRunner.run_checks()
+.. method:: DiscoverRunner.run_checks(databases)
 
-    Runs the :doc:`system checks </topics/checks>`.
+    Runs the :doc:`system checks </topics/checks>` on the test ``databases``.
+
+    .. versionadded:: 3.1
+
+        The ``databases`` parameter was added.
 
 .. method:: DiscoverRunner.run_suite(suite, **kwargs)