Add tests.

superset/models/helpers.py

@@ -1377,7 +1377,7 @@ def values_for_column(
             qry = qry.where(self.get_fetch_values_predicate(template_processor=tp))
 
         with self.database.get_sqla_engine() as engine:
-            sql = qry.compile(engine, compile_kwargs={"literal_binds": True})
+            sql = str(qry.compile(engine, compile_kwargs={"literal_binds": True}))
             sql = self._apply_cte(sql, cte)
             sql = self.database.mutate_sql_based_on_config(sql)
 

tests/unit_tests/models/helpers_test.py

@@ -17,22 +17,24 @@
 
 # pylint: disable=import-outside-toplevel
 
+from __future__ import annotations
+
 from contextlib import contextmanager
+from typing import TYPE_CHECKING
 
+import pytest
 from pytest_mock import MockerFixture
 from sqlalchemy import create_engine
 from sqlalchemy.orm.session import Session
 from sqlalchemy.pool import StaticPool
 
+if TYPE_CHECKING:
+    from superset.models.core import Database
 
-def test_values_for_column(mocker: MockerFixture, session: Session) -> None:
-    """
-    Test the `values_for_column` method.
 
-    NULL values should be returned as `None`, not `np.nan`, since NaN cannot be
-    serialized to JSON.
-    """
-    from superset.connectors.sqla.models import SqlaTable, TableColumn
+@pytest.fixture()
+def database(mocker: MockerFixture, session: Session) -> Database:
+    from superset.connectors.sqla.models import SqlaTable
     from superset.models.core import Database
 
     SqlaTable.metadata.create_all(session.get_bind())
@@ -42,13 +44,12 @@ def test_values_for_column(mocker: MockerFixture, session: Session) -> None:
         connect_args={"check_same_thread": False},
         poolclass=StaticPool,
     )
-
     database = Database(database_name="db", sqlalchemy_uri="sqlite://")
 
     connection = engine.raw_connection()
-    connection.execute("CREATE TABLE t (c INTEGER)")
-    connection.execute("INSERT INTO t VALUES (1)")
-    connection.execute("INSERT INTO t VALUES (NULL)")
+    connection.execute("CREATE TABLE t (a INTEGER, b TEXT)")
+    connection.execute("INSERT INTO t VALUES (1, 'Alice')")
+    connection.execute("INSERT INTO t VALUES (NULL, 'Bob')")
     connection.commit()
 
     # since we're using an in-memory SQLite database, make sure we always
@@ -63,10 +64,94 @@ def mock_get_sqla_engine():
         new=mock_get_sqla_engine,
     )
 
+    return database
+
+
+def test_values_for_column(database: Database) -> None:
+    """
+    Test the `values_for_column` method.
+
+    NULL values should be returned as `None`, not `np.nan`, since NaN cannot be
+    serialized to JSON.
+    """
+    from superset.connectors.sqla.models import SqlaTable, TableColumn
+
+    table = SqlaTable(
+        database=database,
+        schema=None,
+        table_name="t",
+        columns=[TableColumn(column_name="a")],
+    )
+    assert table.values_for_column("a") == [1, None]
+
+
+def test_values_for_column_calculated(
+    mocker: MockerFixture,
+    database: Database,
+) -> None:
+    """
+    Test that calculated columns work.
+    """
+    from superset.connectors.sqla.models import SqlaTable, TableColumn
+
+    table = SqlaTable(
+        database=database,
+        schema=None,
+        table_name="t",
+        columns=[
+            TableColumn(
+                column_name="starts_with_A",
+                expression="CASE WHEN b LIKE 'A%' THEN 'yes' ELSE 'nope' END",
+            )
+        ],
+    )
+    assert table.values_for_column("starts_with_A") == ["yes", "nope"]
+
+
+def test_values_for_column_double_percents(
+    mocker: MockerFixture,
+    database: Database,
+) -> None:
+    """
+    Test the behavior of `double_percents`.
+    """
+    from superset.connectors.sqla.models import SqlaTable, TableColumn
+
+    with database.get_sqla_engine() as engine:
+        engine.dialect.identifier_preparer._double_percents = "pyformat"
+
     table = SqlaTable(
         database=database,
         schema=None,
         table_name="t",
-        columns=[TableColumn(column_name="c")],
+        columns=[
+            TableColumn(
+                column_name="starts_with_A",
+                expression="CASE WHEN b LIKE 'A%' THEN 'yes' ELSE 'nope' END",
+            )
+        ],
+    )
+
+    mutate_sql_based_on_config = mocker.patch.object(
+        database,
+        "mutate_sql_based_on_config",
+        side_effect=lambda sql: sql,
+    )
+    pd = mocker.patch("superset.models.helpers.pd")
+
+    table.values_for_column("starts_with_A")
+
+    # make sure the SQL originally had double percents
+    mutate_sql_based_on_config.assert_called_with(
+        "SELECT DISTINCT CASE WHEN b LIKE 'A%%' THEN 'yes' ELSE 'nope' END "
+        "AS column_values \nFROM t\n LIMIT 10000 OFFSET 0"
     )
-    assert table.values_for_column("c") == [1, None]
+    # make sure final query has single percents
+    with database.get_sqla_engine() as engine:
+        pd.read_sql_query.assert_called_with(
+            sql=(
+                "SELECT DISTINCT CASE WHEN b LIKE 'A%' THEN 'yes' ELSE 'nope' END "
+                "AS column_values \nFROM t\n LIMIT 10000 OFFSET 0"
+            ),
+            con=engine,
+        )