866 lines
30 KiB
Python

# Copyright 2025 Collate
# Licensed under the Collate Community License, Version 1.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
# https://github.com/open-metadata/OpenMetadata/blob/main/ingestion/LICENSE
# 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.
"""
Test databricks using the topology
"""
# pylint: disable=invalid-name,import-outside-toplevel
from unittest import TestCase
from unittest.mock import MagicMock, Mock, patch
from metadata.generated.schema.api.data.createDatabaseSchema import (
CreateDatabaseSchemaRequest,
)
from metadata.generated.schema.api.data.createTable import CreateTableRequest
from metadata.generated.schema.entity.data.database import Database
from metadata.generated.schema.entity.data.databaseSchema import DatabaseSchema
from metadata.generated.schema.entity.data.table import Column, DataType, TableType
from metadata.generated.schema.entity.services.databaseService import (
DatabaseConnection,
DatabaseService,
DatabaseServiceType,
)
from metadata.generated.schema.metadataIngestion.workflow import (
OpenMetadataWorkflowConfig,
)
from metadata.generated.schema.type.basic import FullyQualifiedEntityName
from metadata.generated.schema.type.entityReference import EntityReference
from metadata.ingestion.ometa.utils import model_str
from metadata.ingestion.source.database.databricks.metadata import DatabricksSource
mock_databricks_config = {
"source": {
"type": "databricks",
"serviceName": "local_datalake",
"serviceConnection": {
"config": {
"type": "Databricks",
"catalog": "hive_metastore",
"databaseSchema": "default",
"token": "123sawdtesttoken",
"hostPort": "localhost:443",
"httpPath": "/sql/1.0/warehouses/abcdedfg",
"connectionArguments": {"http_path": "/sql/1.0/warehouses/abcdedfg"},
}
},
"sourceConfig": {
"config": {
"type": "DatabaseMetadata",
"schemaFilterPattern": {"excludes": []},
}
},
},
"sink": {"type": "metadata-rest", "config": {}},
"workflowConfig": {
"openMetadataServerConfig": {
"hostPort": "http://localhost:8585/api",
"authProvider": "openmetadata",
"securityConfig": {"jwtToken": "databricks"},
}
},
}
MOCK_TABLE = {
"id": "2d725b6e-1588-4814-9d8b-eff384cd1053",
"name": "DataSet Input",
"description": "this is a description for dataset input",
"rows": 99,
"columns": 10,
"schema": {
"columns": [
{"type": "DOUBLE", "name": "amount"},
{"type": "DOUBLE", "name": "bank_transfer_amount"},
{"type": "DOUBLE", "name": "coupon_amount"},
{"type": "DOUBLE", "name": "credit_card_amount"},
]
},
"owner": {"id": 1027954122, "name": "Nihar Doshi"},
"dataCurrentAt": "2022-10-18T05:30:06Z",
"createdAt": "2022-10-17T05:52:21Z",
"updatedAt": "2022-10-18T05:30:07Z",
"pdpEnabled": False,
"policies": [
{
"id": 17,
"type": "open",
"name": "All Rows",
"filters": [],
"users": [],
"virtualUsers": [],
"groups": [],
}
],
}
MOCK_TABLE_2 = {
"id": "3df43ed7-5f2f-46bb-9793-384c6374a81d",
"name": "growth data",
"description": "company growth data",
"rows": 5,
"columns": 2,
"schema": {
"columns": [
{"type": "ARRAY", "name": "quarters.result"},
{"type": "NUMBER", "name": "profit"},
]
},
"owner": {"id": 6024954162, "name": "Sam"},
"dataCurrentAt": "2024-07-15T05:30:06Z",
"createdAt": "2024-07-15T05:52:21Z",
"updatedAt": "2024-07-15T05:30:07Z",
}
EXPTECTED_TABLE_2 = [
CreateTableRequest(
name="growth data",
displayName="growth data",
description="company growth data",
tableType=TableType.Regular.value,
columns=[
Column(
name="quarters.result",
dataType=DataType.ARRAY.value,
),
Column(
name="profit",
dataType=DataType.NUMBER.value,
),
],
databaseSchema=FullyQualifiedEntityName(
"local_databricks.hive_metastore.do_it_all_with_default_schema"
),
)
]
EXPECTED_DATABASE_NAMES = ["hive_metastore"]
EXPECTED_DATABASE_SCHEMA_NAMES = ["default"]
MOCK_DATABASE_SERVICE = DatabaseService(
id="85811038-099a-11ed-861d-0242ac120002",
name="local_databricks",
connection=DatabaseConnection(),
serviceType=DatabaseServiceType.Databricks,
)
MOCK_DATABASE = Database(
id="a4e2f4aa-10af-4d4b-a85b-5daad6f70720",
name="hive_metastore",
fullyQualifiedName="local_databricks.hive_metastore",
displayName="hive_metastore",
description="",
service=EntityReference(
id="85811038-099a-11ed-861d-0242ac120002", type="databaseService"
),
)
MOCK_DATABASE_SCHEMA = DatabaseSchema(
id="ec5be98f-917c-44be-b178-47b3237ef648",
name="do_it_all_with_default_schema",
fullyQualifiedName="domodatabase_source.do_it_all_with_default_config.do_it_all_with_default_schema",
service=EntityReference(id="ec5be98f-917c-44be-b178-47b3237ef648", type="database"),
database=EntityReference(
id="a4e2f4aa-10af-4d4b-a85b-5daad6f70720",
type="database",
),
)
EXPTECTED_DATABASE_SCHEMA = [
CreateDatabaseSchemaRequest(
name="do_it_all_with_default_schema",
displayName=None,
description=None,
owners=None,
database="local_databricks.hive_metastore",
)
]
EXPTECTED_TABLE = [
CreateTableRequest(
name="newtable",
displayName="newtable",
description="this is a description for dataset input",
tableType=TableType.Regular.value,
columns=[
Column(
name="amount",
displayName=None,
dataType=DataType.DOUBLE.value,
arrayDataType=None,
dataLength=None,
precision=None,
scale=None,
dataTypeDisplay=None,
description="",
fullyQualifiedName=None,
tags=None,
constraint=None,
ordinalPosition=1,
jsonSchema=None,
children=None,
customMetrics=None,
profile=None,
),
Column(
name="bank_transfer_amount",
displayName=None,
dataType=DataType.DOUBLE.value,
arrayDataType=None,
dataLength=None,
precision=None,
scale=None,
dataTypeDisplay=None,
description="",
fullyQualifiedName=None,
tags=None,
constraint=None,
ordinalPosition=2,
jsonSchema=None,
children=None,
customMetrics=None,
profile=None,
),
Column(
name="coupon_amount",
displayName=None,
dataType=DataType.DOUBLE.value,
arrayDataType=None,
dataLength=None,
precision=None,
scale=None,
dataTypeDisplay=None,
description="",
fullyQualifiedName=None,
tags=None,
constraint=None,
ordinalPosition=3,
jsonSchema=None,
children=None,
customMetrics=None,
profile=None,
),
Column(
name="credit_card_amount",
displayName=None,
dataType=DataType.DOUBLE.value,
arrayDataType=None,
dataLength=None,
precision=None,
scale=None,
dataTypeDisplay=None,
description="",
fullyQualifiedName=None,
tags=None,
constraint=None,
ordinalPosition=4,
jsonSchema=None,
children=None,
customMetrics=None,
profile=None,
),
],
tableConstraints=None,
tablePartition=None,
tableProfilerConfig=None,
owners=None,
databaseSchema=FullyQualifiedEntityName(
"local_databricks.hive_metastore.do_it_all_with_default_schema"
),
tags=None,
schemaDefinition=None,
extension=None,
)
]
class DatabricksUnitTest(TestCase):
"""
Databricks unit tests
"""
@patch(
"metadata.ingestion.source.database.common_db_source.CommonDbSourceService.test_connection"
)
@patch(
"metadata.ingestion.source.database.databricks.metadata.DatabricksSource._init_version"
)
def __init__(self, methodName, test_connection, db_init_version) -> None:
super().__init__(methodName)
test_connection.return_value = False
db_init_version.return_value = None
self.config = OpenMetadataWorkflowConfig.model_validate(mock_databricks_config)
self.databricks_source = DatabricksSource.create(
mock_databricks_config["source"],
self.config.workflowConfig.openMetadataServerConfig,
)
self.databricks_source.context.get().__dict__[
"database"
] = MOCK_DATABASE.name.root
self.databricks_source.context.get().__dict__[
"database_service"
] = MOCK_DATABASE_SERVICE.name.root
self.databricks_source.context.get().__dict__[
"database_schema"
] = MOCK_DATABASE_SCHEMA.name.root
def test_database_schema_names(self):
assert EXPECTED_DATABASE_SCHEMA_NAMES == list(
self.databricks_source.get_database_schema_names()
)
def test_raw_database_schema_names(self):
assert EXPECTED_DATABASE_SCHEMA_NAMES == list(
self.databricks_source.get_raw_database_schema_names()
)
def test_yield_schema(self):
schema_list = []
yield_schemas = self.databricks_source.yield_database_schema(
schema_name=model_str(MOCK_DATABASE_SCHEMA.name)
)
for schema in yield_schemas:
if isinstance(schema, CreateDatabaseSchemaRequest):
schema_list.append(schema)
for _, (exptected, original) in enumerate(
zip(EXPTECTED_DATABASE_SCHEMA, schema_list)
):
self.assertEqual(exptected, original)
def test_yield_table(self):
table_list = []
yield_tables = self.databricks_source.yield_table(
("2d725b6e-1588-4814-9d8b-eff384cd1053", "Regular")
)
for table in yield_tables:
if isinstance(table, CreateTableRequest):
table_list.append(table)
for _, (expected, original) in enumerate(zip(EXPTECTED_TABLE, table_list)):
self.assertEqual(expected, original)
def test_yield_table_2(self):
table_list = []
yield_tables = self.databricks_source.yield_table(
("3df43ed7-5f2f-46bb-9793-384c6374a81d", "Regular")
)
for table in yield_tables:
if isinstance(table, CreateTableRequest):
table_list.append(table)
for _, (expected, original) in enumerate(zip(EXPTECTED_TABLE_2, table_list)):
self.assertEqual(expected, original)
class DatabricksConnectionTest(TestCase):
"""
Unit tests for Databricks connection functionality
"""
def setUp(self):
"""Set up test fixtures"""
from metadata.generated.schema.entity.services.connections.database.databricksConnection import (
DatabricksConnection,
DatabricksScheme,
)
from metadata.ingestion.source.database.databricks.connection import (
DatabricksEngineWrapper,
get_connection,
get_connection_url,
test_connection,
)
self.DatabricksEngineWrapper = DatabricksEngineWrapper
self.get_connection_url = get_connection_url
self.get_connection = get_connection
self.test_connection = test_connection
self.DatabricksConnection = DatabricksConnection
self.DatabricksScheme = DatabricksScheme
def test_get_connection_url(self):
"""Test get_connection_url function"""
connection = self.DatabricksConnection(
scheme=self.DatabricksScheme.databricks_connector,
hostPort="test-host:443",
token="test-token",
httpPath="/sql/1.0/warehouses/test",
)
url = self.get_connection_url(connection)
expected_url = "databricks+connector://token:test-token@test-host:443"
self.assertEqual(url, expected_url)
@patch(
"metadata.ingestion.source.database.databricks.connection.create_generic_db_connection"
)
def test_get_connection(self, mock_create_connection):
"""Test get_connection function"""
connection = self.DatabricksConnection(
scheme=self.DatabricksScheme.databricks_connector,
hostPort="test-host:443",
token="test-token",
httpPath="/sql/1.0/warehouses/test",
)
mock_engine = Mock()
mock_create_connection.return_value = mock_engine
result = self.get_connection(connection)
self.assertEqual(result, mock_engine)
mock_create_connection.assert_called_once()
def test_databricks_engine_wrapper_initialization(self):
"""Test DatabricksEngineWrapper initialization"""
mock_engine = Mock()
mock_inspector = Mock()
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
self.assertEqual(wrapper.engine, mock_engine)
self.assertEqual(wrapper.inspector, mock_inspector)
self.assertIsNone(wrapper.schemas)
self.assertIsNone(wrapper.first_schema)
def test_databricks_engine_wrapper_get_schemas_with_non_system_schemas(self):
"""Test get_schemas with non-system schemas"""
mock_engine = Mock()
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = [
"information_schema",
"test_schema",
"performance_schema",
]
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
schemas = wrapper.get_schemas()
self.assertEqual(
schemas, ["information_schema", "test_schema", "performance_schema"]
)
self.assertEqual(wrapper.first_schema, "test_schema")
self.assertEqual(
wrapper.schemas,
["information_schema", "test_schema", "performance_schema"],
)
def test_databricks_engine_wrapper_get_schemas_with_only_system_schemas(self):
"""Test get_schemas with only system schemas"""
mock_engine = Mock()
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = [
"information_schema",
"performance_schema",
]
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
schemas = wrapper.get_schemas()
self.assertEqual(schemas, ["information_schema", "performance_schema"])
self.assertEqual(wrapper.first_schema, "information_schema")
self.assertEqual(
wrapper.schemas, ["information_schema", "performance_schema"]
)
def test_databricks_engine_wrapper_get_schemas_empty(self):
"""Test get_schemas with empty schema list"""
mock_engine = Mock()
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = []
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
schemas = wrapper.get_schemas()
self.assertEqual(schemas, [])
self.assertIsNone(wrapper.first_schema)
self.assertEqual(wrapper.schemas, [])
def test_databricks_engine_wrapper_get_tables_with_cached_schema(self):
"""Test get_tables with cached schema"""
mock_engine = Mock()
mock_connection = Mock()
mock_context_manager = MagicMock()
mock_context_manager.__enter__.return_value = mock_connection
mock_context_manager.__exit__.return_value = None
mock_engine.connect.return_value = mock_context_manager
# Mock the connection execute method to return a result
mock_result = Mock()
mock_result.fetchall.return_value = [("table1",), ("table2",)]
mock_connection.execute.return_value = mock_result
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = [
"test_schema",
"information_schema",
]
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
# Set the first_catalog for the wrapper
wrapper.first_catalog = "test_catalog"
# First call to get_schemas to set first_schema
wrapper.get_schemas()
# Then call get_tables
tables = wrapper.get_tables()
self.assertEqual(tables, mock_result)
mock_connection.execute.assert_called_once()
def test_databricks_engine_wrapper_get_tables_without_cached_schema(self):
"""Test get_tables without cached schema"""
mock_engine = Mock()
mock_connection = Mock()
mock_context_manager = MagicMock()
mock_context_manager.__enter__.return_value = mock_connection
mock_context_manager.__exit__.return_value = None
mock_engine.connect.return_value = mock_context_manager
# Mock the connection execute method to return a result
mock_result = Mock()
mock_result.fetchall.return_value = [("table1",), ("table2",)]
mock_connection.execute.return_value = mock_result
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = [
"test_schema",
"information_schema",
]
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
# Set the first_catalog for the wrapper
wrapper.first_catalog = "test_catalog"
# Call get_tables directly without calling get_schemas first
tables = wrapper.get_tables()
self.assertEqual(tables, mock_result)
# Should have called get_schemas internally
mock_inspector.get_schema_names.assert_called_once()
mock_connection.execute.assert_called_once()
def test_databricks_engine_wrapper_get_tables_no_schemas(self):
"""Test get_tables when no schemas are available"""
mock_engine = Mock()
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = []
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
tables = wrapper.get_tables()
self.assertEqual(tables, [])
mock_inspector.get_table_names.assert_not_called()
def test_databricks_engine_wrapper_get_views_with_cached_schema(self):
"""Test get_views with cached schema"""
mock_engine = Mock()
mock_connection = Mock()
mock_context_manager = MagicMock()
mock_context_manager.__enter__.return_value = mock_connection
mock_context_manager.__exit__.return_value = None
mock_engine.connect.return_value = mock_context_manager
# Mock the connection execute method to return a result
mock_result = Mock()
mock_result.fetchall.return_value = [("view1",), ("view2",)]
mock_connection.execute.return_value = mock_result
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = [
"test_schema",
"information_schema",
]
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
# Set the first_catalog for the wrapper
wrapper.first_catalog = "test_catalog"
# First call to get_schemas to set first_schema
wrapper.get_schemas()
# Then call get_views
views = wrapper.get_views()
self.assertEqual(views, mock_result)
mock_connection.execute.assert_called_once()
def test_databricks_engine_wrapper_get_views_without_cached_schema(self):
"""Test get_views without cached schema"""
mock_engine = Mock()
mock_connection = Mock()
mock_context_manager = MagicMock()
mock_context_manager.__enter__.return_value = mock_connection
mock_context_manager.__exit__.return_value = None
mock_engine.connect.return_value = mock_context_manager
# Mock the connection execute method to return a result
mock_result = Mock()
mock_result.fetchall.return_value = [("view1",), ("view2",)]
mock_connection.execute.return_value = mock_result
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = [
"test_schema",
"information_schema",
]
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
# Set the first_catalog for the wrapper
wrapper.first_catalog = "test_catalog"
# Call get_views directly without calling get_schemas first
views = wrapper.get_views()
self.assertEqual(views, mock_result)
# Should have called get_schemas internally
mock_inspector.get_schema_names.assert_called_once()
mock_connection.execute.assert_called_once()
def test_databricks_engine_wrapper_get_views_no_schemas(self):
"""Test get_views when no schemas are available"""
mock_engine = Mock()
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = []
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
views = wrapper.get_views()
self.assertEqual(views, [])
mock_inspector.get_view_names.assert_not_called()
def test_databricks_engine_wrapper_caching_behavior(self):
"""Test that schemas are cached and not fetched multiple times"""
mock_engine = Mock()
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = [
"test_schema",
"information_schema",
]
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
# Call get_schemas multiple times
schemas1 = wrapper.get_schemas()
schemas2 = wrapper.get_schemas()
schemas3 = wrapper.get_schemas()
# All calls should return the same result
self.assertEqual(schemas1, schemas2)
self.assertEqual(schemas2, schemas3)
# get_schema_names should only be called once due to caching
mock_inspector.get_schema_names.assert_called_once()
# pylint: disable=too-many-locals
@patch(
"metadata.ingestion.source.database.databricks.connection.test_connection_steps"
)
def test_test_connection_function(self, mock_test_connection_steps):
"""Test the test_connection function"""
from metadata.generated.schema.entity.services.connections.database.databricksConnection import (
DatabricksConnection,
DatabricksScheme,
)
from metadata.generated.schema.entity.services.connections.testConnectionResult import (
StatusType,
TestConnectionResult,
TestConnectionStepResult,
)
# Mock the test connection result
mock_result = TestConnectionResult(
status=StatusType.Successful,
steps=[
TestConnectionStepResult(
name="CheckAccess",
mandatory=True,
passed=True,
),
TestConnectionStepResult(
name="GetSchemas",
mandatory=True,
passed=True,
),
TestConnectionStepResult(
name="GetTables",
mandatory=True,
passed=True,
),
TestConnectionStepResult(
name="GetViews",
mandatory=False,
passed=True,
),
],
)
mock_test_connection_steps.return_value = mock_result
# Create test connection
service_connection = DatabricksConnection(
scheme=DatabricksScheme.databricks_connector,
hostPort="test-host:443",
token="test-token",
httpPath="/sql/1.0/warehouses/test",
queryHistoryTable="test_table",
)
mock_engine = Mock()
mock_metadata = Mock()
# Test the function
result = self.test_connection(
metadata=mock_metadata,
connection=mock_engine,
service_connection=service_connection,
)
# Verify the result
self.assertEqual(result, mock_result)
mock_test_connection_steps.assert_called_once()
# Verify the test_fn dictionary was created with the correct functions
call_args = mock_test_connection_steps.call_args
test_fn = call_args[1]["test_fn"]
# Check that the test_fn contains the expected keys
expected_keys = [
"CheckAccess",
"GetSchemas",
"GetTables",
"GetViews",
"GetDatabases",
"GetQueries",
]
for key in expected_keys:
self.assertIn(key, test_fn)
self.assertIsNotNone(test_fn[key])
def test_databricks_engine_wrapper_system_schema_filtering(self):
"""Test that system schemas are properly filtered out"""
mock_engine = Mock()
mock_inspector = Mock()
# Test with various system schema names
mock_inspector.get_schema_names.return_value = [
"information_schema",
"performance_schema",
"sys",
"SYS",
"INFORMATION_SCHEMA",
"user_schema",
"test_schema",
]
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
schemas = wrapper.get_schemas()
# Should return all schemas
self.assertEqual(
schemas,
[
"information_schema",
"performance_schema",
"sys",
"SYS",
"INFORMATION_SCHEMA",
"user_schema",
"test_schema",
],
)
# Should select the first non-system schema (user_schema)
self.assertEqual(wrapper.first_schema, "user_schema")
def test_databricks_engine_wrapper_all_system_schemas(self):
"""Test behavior when all schemas are system schemas"""
mock_engine = Mock()
mock_inspector = Mock()
mock_inspector.get_schema_names.return_value = [
"information_schema",
"performance_schema",
"sys",
]
with patch(
"metadata.ingestion.source.database.databricks.connection.inspect"
) as mock_inspect:
mock_inspect.return_value = mock_inspector
wrapper = self.DatabricksEngineWrapper(mock_engine)
schemas = wrapper.get_schemas()
# Should return all schemas
self.assertEqual(
schemas, ["information_schema", "performance_schema", "sys"]
)
# Should fall back to the first schema when all are system schemas
self.assertEqual(wrapper.first_schema, "information_schema")