Flask App factory PR #1 (#8418)

* First cut at app factory

* Setting things back to master

* Working with new FLASK_APP

* Still need to refactor Celery

* CLI mostly working

* Working on unit tests

* Moving cli stuff around a bit

* Removing get in config

* Defaulting test config

* Adding flask-testing

* flask-testing casing

* resultsbackend property bug

* Fixing up cli

* Quick fix for KV api

* Working on save slice

* Fixed core_tests

* Fixed utils_tests

* Most tests working - still need to dig into remaining app_context issue in tests

* All tests passing locally - need to update code comments

* Fixing dashboard tests again

* Blacking

* Sorting imports

* linting

* removing envvar mangling

* blacking

* Fixing unit tests

* isorting

* licensing

* fixing mysql tests

* fixing cypress?

* fixing .flaskenv

* fixing test app_ctx

* fixing cypress

* moving manifest processor around

* moving results backend manager around

* Cleaning up __init__ a bit more

* Addressing PR comments

* Addressing PR comments

* Blacking

* Fixes for running celery worker

* Tuning isort

* Blacking

tests/feature_flag_tests.py

@@ -0,0 +1,40 @@
+# 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 unittest.mock import patch
+
+from superset import is_feature_enabled
+from tests.base_tests import SupersetTestCase
+
+
+class FeatureFlagTests(SupersetTestCase):
+    @patch.dict(
+        "superset.extensions.feature_flag_manager._feature_flags",
+        {"FOO": True},
+        clear=True,
+    )
+    def test_existing_feature_flags(self):
+        self.assertTrue(is_feature_enabled("FOO"))
+
+    @patch.dict(
+        "superset.extensions.feature_flag_manager._feature_flags", {}, clear=True
+    )
+    def test_nonexistent_feature_flags(self):
+        self.assertFalse(is_feature_enabled("FOO"))
+
+    def test_feature_flags(self):
+        self.assertEqual(is_feature_enabled("foo"), "bar")
+        self.assertEqual(is_feature_enabled("super"), "set")