add test

dbbackup/management/commands/dbbackup.py

@@ -80,11 +80,8 @@ def handle(self, **options):
         self.storage = get_storage()
 
         self.database = options.get("database") or ""
-        database_keys = (
-            self.database.split(",") if self.database else settings.DATABASES
-        )
 
-        for database_key in database_keys:
+        for database_key in self._get_database_keys():
             self.connector = get_connector(database_key)
             if self.connector and self.exclude_tables:
                 self.connector.exclude.extend(
@@ -98,6 +95,9 @@ def handle(self, **options):
             except StorageError as err:
                 raise CommandError(err) from err
 
+    def _get_database_keys(self):
+        return self.database.split(",") if self.database else settings.DATABASES
+
     def _save_new_backup(self, database):
         """
         Save a new backup file.

dbbackup/tests/commands/test_dbbackup.py

@@ -50,6 +50,16 @@ def test_path(self):
         # tearDown
         os.remove(self.command.path)
 
+    @patch("dbbackup.settings.DATABASES", ["db-from-settings"])
+    def test_get_database_keys(self):
+        with self.subTest("use --database from CLI"):
+            self.command.database = "db-from-cli"
+            self.assertEqual(self.command._get_database_keys(), ["db-from-cli"])
+
+        with self.subTest("fallback to DBBACKUP_DATABASES"):
+            self.command.database = ""
+            self.assertEqual(self.command._get_database_keys(), ["db-from-settings"])
+
 
 @patch("dbbackup.settings.GPG_RECIPIENT", "test@test")
 @patch("sys.stdout", DEV_NULL)