test non-imglist db

py-packages/imagelist2/imagelist2/db.py

@@ -75,6 +75,15 @@ class DB:
                 return
             db.close()
         except Exception:
+            # Test if it's an image-list DB at all:
+            try:
+                db = sqlite3.connect(self.sqlfile, timeout=30)
+                db.execute("SELECT 1 FROM data")
+                db.execute("SELECT 1 FROM list")
+                db.execute("SELECT 1 FROM files")
+            except sqlite3.OperationalError:
+                raise Exception("Database is not image-list DB")
+
             # last version without config
             config_version = "0.0.6"
         self.migrated = True