Fixed #27077 -- Made SQLite's in-memory database checks DRYer.

3 files changed, 15 insertions, 10 deletions

diff --git a/django/db/backends/sqlite3/base.py b/django/db/backends/sqlite3/base.py
index 870dc10353..0d6b4e3d00 100644
--- a/django/db/backends/sqlite3/base.py
+++ b/django/db/backends/sqlite3/base.py
@@ -233,7 +233,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         # If database is in memory, closing the connection destroys the
         # database. To prevent accidental data loss, ignore close requests on
         # an in-memory db.
-        if not self.is_in_memory_db(self.settings_dict['NAME']):
+        if not self.is_in_memory_db():
             BaseDatabaseWrapper.close(self)
 
     def _savepoint_allowed(self):
@@ -319,8 +319,8 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         """
         self.cursor().execute("BEGIN")
 
-    def is_in_memory_db(self, name):
-        return name == ":memory:" or "mode=memory" in force_text(name)
+    def is_in_memory_db(self):
+        return self.creation.is_in_memory_db(self.settings_dict['NAME'])
 
 
 FORMAT_QMARK_REGEX = re.compile(r'(?<!%)%s')
diff --git a/django/db/backends/sqlite3/creation.py b/django/db/backends/sqlite3/creation.py
index 26ad0d4f95..33661e1357 100644
--- a/django/db/backends/sqlite3/creation.py
+++ b/django/db/backends/sqlite3/creation.py
@@ -4,11 +4,16 @@ import sys
 
 from django.core.exceptions import ImproperlyConfigured
 from django.db.backends.base.creation import BaseDatabaseCreation
+from django.utils.encoding import force_text
 from django.utils.six.moves import input
 
 
 class DatabaseCreation(BaseDatabaseCreation):
 
+    @staticmethod
+    def is_in_memory_db(database_name):
+        return database_name == ':memory:' or 'mode=memory' in force_text(database_name)
+
     def _get_test_db_name(self):
         test_database_name = self.connection.settings_dict['TEST']['NAME']
         can_share_in_memory_db = self.connection.features.can_share_in_memory_db
@@ -30,7 +35,7 @@ class DatabaseCreation(BaseDatabaseCreation):
 
         if keepdb:
             return test_database_name
-        if not self.connection.is_in_memory_db(test_database_name):
+        if not self.is_in_memory_db(test_database_name):
             # Erase the old test database
             if verbosity >= 1:
                 print("Destroying old test database for alias %s..." % (
@@ -56,7 +61,7 @@ class DatabaseCreation(BaseDatabaseCreation):
     def get_test_db_clone_settings(self, number):
         orig_settings_dict = self.connection.settings_dict
         source_database_name = orig_settings_dict['NAME']
-        if self.connection.is_in_memory_db(source_database_name):
+        if self.is_in_memory_db(source_database_name):
             return orig_settings_dict
         else:
             new_settings_dict = orig_settings_dict.copy()
@@ -68,7 +73,7 @@ class DatabaseCreation(BaseDatabaseCreation):
         source_database_name = self.connection.settings_dict['NAME']
         target_database_name = self.get_test_db_clone_settings(number)['NAME']
         # Forking automatically makes a copy of an in-memory database.
-        if not self.connection.is_in_memory_db(source_database_name):
+        if not self.is_in_memory_db(source_database_name):
             # Erase the old test database
             if os.access(target_database_name, os.F_OK):
                 if keepdb:
@@ -89,7 +94,7 @@ class DatabaseCreation(BaseDatabaseCreation):
                 sys.exit(2)
 
     def _destroy_test_db(self, test_database_name, verbosity):
-        if test_database_name and not self.connection.is_in_memory_db(test_database_name):
+        if test_database_name and not self.is_in_memory_db(test_database_name):
             # Remove the SQLite database file
             os.remove(test_database_name)
 
@@ -103,6 +108,6 @@ class DatabaseCreation(BaseDatabaseCreation):
         """
         test_database_name = self._get_test_db_name()
         sig = [self.connection.settings_dict['NAME']]
-        if self.connection.is_in_memory_db(test_database_name):
+        if self.is_in_memory_db(test_database_name):
             sig.append(self.connection.alias)
         return tuple(sig)
diff --git a/django/test/testcases.py b/django/test/testcases.py
index 2220ec7f52..399c8adf57 100644
--- a/django/test/testcases.py
+++ b/django/test/testcases.py
@@ -1299,7 +1299,7 @@ class LiveServerTestCase(TransactionTestCase):
         for conn in connections.all():
             # If using in-memory sqlite databases, pass the connections to
             # the server thread.
-            if conn.vendor == 'sqlite' and conn.is_in_memory_db(conn.settings_dict['NAME']):
+            if conn.vendor == 'sqlite' and conn.is_in_memory_db():
                 # Explicitly enable thread-shareability for this connection
                 conn.allow_thread_sharing = True
                 connections_override[conn.alias] = conn
@@ -1339,7 +1339,7 @@ class LiveServerTestCase(TransactionTestCase):
 
         # Restore sqlite in-memory database connections' non-shareability
         for conn in connections.all():
-            if conn.vendor == 'sqlite' and conn.is_in_memory_db(conn.settings_dict['NAME']):
+            if conn.vendor == 'sqlite' and conn.is_in_memory_db():
                 conn.allow_thread_sharing = False
 
     @classmethod