Fix ATTACH-dependent tests

Author: barbieri

sqlalchemy_libsql/requirements.py

@@ -53,6 +53,7 @@ def _sqlite_attach(self, config):
             cursor = connection.cursor()
             try:
                 cursor.execute("ATTACH ':memory:' AS test_schema")
+                cursor.execute("DETACH test_schema")
                 return True
             except:
                 return False

test/test_suite.py

@@ -1743,6 +1743,7 @@ def test_reflect_tables_fk_no_colref(self):
 
 
 class KeywordInDatabaseNameTest(fixtures.TestBase):
+    __requires__ = ("sqlite_attach",)
     __only_on__ = "sqlite"
     __backend__ = True