Fixed #20550 -- Added keepdb argument to destroy_test_db

AUTHORS

@@ -154,6 +154,7 @@ answer newbie questions, and generally made Django that much better:
     Antonio Cavedoni <http://cavedoni.com/>
     cedric@terramater.net
     Chris Chamberlin <dja@cdc.msbx.net>
+    Greg Chapple <gregchapple1@gmail.com>
     Amit Chakradeo <http://amit.chakradeo.net/>
     ChaosKCW
     Kowito Charoenratchatabhan <kowito@felspar.com>

django/db/backends/creation.py

@@ -449,7 +449,7 @@ class BaseDatabaseCreation(object):
 
         return test_database_name
 
-    def destroy_test_db(self, old_database_name, verbosity=1):
+    def destroy_test_db(self, old_database_name, verbosity=1, keepdb=False):
         """
         Destroy a test database, prompting the user for confirmation if the
         database already exists.
@@ -458,12 +458,18 @@ class BaseDatabaseCreation(object):
         test_database_name = self.connection.settings_dict['NAME']
         if verbosity >= 1:
             test_db_repr = ''
+            action = 'Destroying'
             if verbosity >= 2:
                 test_db_repr = " ('%s')" % test_database_name
-            print("Destroying test database for alias '%s'%s..." % (
+            if keepdb:
-                self.connection.alias, test_db_repr))
+                action = 'Preserving'
+            print("%s test database for alias '%s'%s..." % (
+                action, self.connection.alias, test_db_repr))
 
-        self._destroy_test_db(test_database_name, verbosity)
+        # if we want to preserve the database
+        # skip the actual destroying piece.
+        if not keepdb:
+            self._destroy_test_db(test_database_name, verbosity)
 
     def _destroy_test_db(self, test_database_name, verbosity):
         """

django/test/runner.py

@@ -124,8 +124,8 @@ class DiscoverRunner(object):
         """
         old_names, mirrors = old_config
         for connection, old_name, destroy in old_names:
-            if destroy and not self.keepdb:
+            if destroy:
-                connection.creation.destroy_test_db(old_name, self.verbosity)
+                connection.creation.destroy_test_db(old_name, self.verbosity, self.keepdb)
 
     def teardown_test_environment(self, **kwargs):
         unittest.removeHandler()

docs/topics/testing/advanced.txt

@@ -485,7 +485,7 @@ django.db.connection.creation
 The creation module of the database backend also provides some utilities that
 can be useful during testing.
 
-.. function:: create_test_db([verbosity=1, autoclobber=False])
+.. function:: create_test_db([verbosity=1, autoclobber=False, keepdb=False])
 
     Creates a new test database and runs ``migrate`` against it.
 
@@ -501,13 +501,19 @@ can be useful during testing.
     * If autoclobber is ``True``, the database will be destroyed
       without consulting the user.
 
+    ``keepdb`` determines if the test run should use an existing
+    database, or create a new one. If ``True``, the existing
+    database will be used, or created if not present. If ``False``,
+    a new database will be created, prompting the user to remove
+    the existing one, if present.
+
     Returns the name of the test database that it created.
 
     ``create_test_db()`` has the side effect of modifying the value of
     :setting:`NAME` in :setting:`DATABASES` to match the name of the test
     database.
 
-.. function:: destroy_test_db(old_database_name, [verbosity=1])
+.. function:: destroy_test_db(old_database_name, [verbosity=1, keepdb=False])
 
     Destroys the database whose name is the value of :setting:`NAME` in
     :setting:`DATABASES`, and sets :setting:`NAME` to the value of
@@ -516,6 +522,9 @@ can be useful during testing.
     The ``verbosity`` argument has the same behavior as for
     :class:`~django.test.runner.DiscoverRunner`.
 
+    If the ``keepdb`` argument is ``True``, then the connection to the
+    database will be closed, but the database will not be destroyed.
+
 .. _topics-testing-code-coverage:
 
 Integration with coverage.py

tests/test_runner/tests.py

@@ -309,7 +309,7 @@ class AliasedDatabaseTeardownTest(unittest.TestCase):
         old_create_test_db = DatabaseCreation.create_test_db
         try:
             destroyed_names = []
-            DatabaseCreation.destroy_test_db = lambda self, old_database_name, verbosity=1: destroyed_names.append(old_database_name)
+            DatabaseCreation.destroy_test_db = lambda self, old_database_name, verbosity=1, keepdb=False: destroyed_names.append(old_database_name)
             DatabaseCreation.create_test_db = lambda self, verbosity=1, autoclobber=False, keepdb=False: self._get_test_db_name()
 
             db.connections = db.ConnectionHandler({