refactor(tests): decouple unittests from integration tests (#15473)

* refactor move all tests to be under integration_tests package

* refactor decouple unittests from integration tests - commands

* add unit_tests package

* fix celery_tests.py

* fix wrong FIXTURES_DIR value

tests/integration_tests/db_engine_specs/ascend_tests.py

@@ -0,0 +1,32 @@
+# 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.
+from superset.db_engine_specs.ascend import AscendEngineSpec
+from tests.integration_tests.db_engine_specs.base_tests import TestDbEngineSpec
+
+
+class TestAscendDbEngineSpec(TestDbEngineSpec):
+    def test_convert_dttm(self):
+        dttm = self.get_dttm()
+
+        self.assertEqual(
+            AscendEngineSpec.convert_dttm("DATE", dttm), "CAST('2019-01-02' AS DATE)"
+        )
+
+        self.assertEqual(
+            AscendEngineSpec.convert_dttm("TIMESTAMP", dttm),
+            "CAST('2019-01-02T03:04:05.678900' AS TIMESTAMP)",
+        )