CI: Check for file leaks in _all_ tests

pandas/conftest.py

@@ -157,6 +157,15 @@ def add_imports(doctest_namespace):
     doctest_namespace["pd"] = pd
 
 
+@pytest.fixture(autouse=True)
+def check_file_leaks():
+    """
+    Check that a test does not leak file handles.
+    """
+    with td.file_leak_context():
+        yield
+
+
 # ----------------------------------------------------------------
 # Common arguments
 # ----------------------------------------------------------------

pandas/io/common.py

@@ -535,6 +535,8 @@ def get_handle(
         try:
             wrapped = _MMapWrapper(f)
             f.close()
+            handles.remove(f)
+            handles.append(wrapped)
             f = wrapped
         except Exception:
             # we catch any errors that may have occurred

pandas/tests/io/test_sql.py

@@ -263,7 +263,8 @@ def _get_all_tables(self):
         return table_list
 
     def _close_conn(self):
-        pass
+        # https://docs.sqlalchemy.org/en/13/core/connections.html#engine-disposal
+        self.conn.dispose()
 
 
 class PandasSQLTest:
@@ -1242,7 +1243,7 @@ class _TestSQLAlchemy(SQLAlchemyMixIn, PandasSQLTest):
     def setup_class(cls):
         cls.setup_import()
         cls.setup_driver()
-        conn = cls.connect()
+        conn = cls.conn = cls.connect()
         conn.connect()
 
     def load_test_data_and_sql(self):