fix(db2): Improving support for ibm db2 connections (#26744)

tests/unit_tests/db_engine_specs/test_db2.py

@@ -0,0 +1,75 @@
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you under the Apache License, Version 2.0 (the
+# "License"); you may not use this file except in compliance
+# with the License.  You may obtain a copy of the License at
+#
+#   http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing,
+# software distributed under the License is distributed on an
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+# KIND, either express or implied.  See the License for the
+# specific language governing permissions and limitations
+# under the License.
+
+import pytest
+from pytest_mock import MockerFixture
+
+
+def test_epoch_to_dttm() -> None:
+    """
+    Test the `epoch_to_dttm` method.
+    """
+    from superset.db_engine_specs.db2 import Db2EngineSpec
+
+    assert (
+        Db2EngineSpec.epoch_to_dttm().format(col="epoch_dttm")
+        == "(TIMESTAMP('1970-01-01', '00:00:00') + epoch_dttm SECONDS)"
+    )
+
+
+def test_get_table_comment(mocker: MockerFixture):
+    """
+    Test the `get_table_comment` method.
+    """
+    from superset.db_engine_specs.db2 import Db2EngineSpec
+
+    mock_inspector = mocker.MagicMock()
+    mock_inspector.get_table_comment.return_value = {
+        "text": ("This is a table comment",)
+    }
+
+    assert (
+        Db2EngineSpec.get_table_comment(mock_inspector, "my_table", "my_schema")
+        == "This is a table comment"
+    )
+
+
+def test_get_table_comment_empty(mocker: MockerFixture):
+    """
+    Test the `get_table_comment` method
+    when no comment is returned.
+    """
+    from superset.db_engine_specs.db2 import Db2EngineSpec
+
+    mock_inspector = mocker.MagicMock()
+    mock_inspector.get_table_comment.return_value = {}
+
+    assert (
+        Db2EngineSpec.get_table_comment(mock_inspector, "my_table", "my_schema") == None
+    )
+
+
+def test_get_prequeries() -> None:
+    """
+    Test the ``get_prequeries`` method.
+    """
+    from superset.db_engine_specs.db2 import Db2EngineSpec
+
+    assert Db2EngineSpec.get_prequeries() == []
+    assert Db2EngineSpec.get_prequeries(schema="my_schema") == [
+        'set current_schema "my_schema"'
+    ]