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/utils/public_interfaces_test.py

@@ -0,0 +1,106 @@
+# 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.
+# pylint: disable=no-self-use
+import pytest
+
+from superset.sql_lab import dummy_sql_query_mutator
+from superset.utils.public_interfaces import compute_hash, get_warning_message
+from tests.integration_tests.base_tests import SupersetTestCase
+
+# These are public interfaces exposed by Superset. Make sure
+# to only change the interfaces and update the hashes in new
+# major versions of Superset.
+hashes = {
+    dummy_sql_query_mutator: "Kv%NM3b;7BcpoD2wbPkW",
+}
+
+
+@pytest.mark.parametrize("interface,expected_hash", list(hashes.items()))
+def test_public_interfaces(interface, expected_hash):
+    """Test that public interfaces have not been accidentally changed."""
+    current_hash = compute_hash(interface)
+    assert current_hash == expected_hash, get_warning_message(interface, current_hash)
+
+
+def test_func_hash():
+    """Test that changing a function signature changes its hash."""
+
+    def some_function(a, b):
+        return a + b
+
+    original_hash = compute_hash(some_function)
+
+    # pylint: disable=function-redefined
+    def some_function(a, b, c):
+        return a + b + c
+
+    assert original_hash != compute_hash(some_function)
+
+
+def test_class_hash():
+    """Test that changing a class changes its hash."""
+
+    # pylint: disable=too-few-public-methods, invalid-name
+    class SomeClass:
+        def __init__(self, a, b):
+            self.a = a
+            self.b = b
+
+        def add(self):
+            return self.a + self.b
+
+    original_hash = compute_hash(SomeClass)
+
+    # changing the __init__ should change the hash
+    # pylint: disable=function-redefined, too-few-public-methods, invalid-name
+    class SomeClass:
+        def __init__(self, a, b, c):
+            self.a = a
+            self.b = b
+            self.c = c
+
+        def add(self):
+            return self.a + self.b
+
+    assert original_hash != compute_hash(SomeClass)
+
+    # renaming a public method should change the hash
+    # pylint: disable=function-redefined, too-few-public-methods, invalid-name
+    class SomeClass:
+        def __init__(self, a, b):
+            self.a = a
+            self.b = b
+
+        def sum(self):
+            return self.a + self.b
+
+    assert original_hash != compute_hash(SomeClass)
+
+    # adding a private method should not change the hash
+    # pylint: disable=function-redefined, too-few-public-methods, invalid-name
+    class SomeClass:
+        def __init__(self, a, b):
+            self.a = a
+            self.b = b
+
+        def add(self):
+            return self._sum()
+
+        def _sum(self):
+            return self.a + self.b
+
+    assert original_hash == compute_hash(SomeClass)