fix to_snowpark_pandas import

src/snowflake/snowpark/dataframe.py

@@ -1005,8 +1005,12 @@ def to_snowpark_pandas(
             B A
             2 1  1  3  1
         """
-        import snowflake.snowpark.modin.pandas as pd  # pragma: no cover
-
+        # black and isort disagree on how to format this section with isort: skip
+        # fmt: off
+        import snowflake.snowpark.modin.plugin  # isort: skip  # noqa: F401
+        # If snowflake.snowpark.modin.plugin was successfully imported, then modin.pandas is available
+        import modin.pandas as pd  # isort: skip
+        # fmt: on
         # create a temporary table out of the current snowpark dataframe
         temporary_table_name = random_name_for_temp_object(
             TempObjectType.TABLE

tests/integ/test_df_to_snowpark_pandas.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2012-2024 Snowflake Computing Inc. All rights reserved.
+#
+
+# Tests behavior of to_snowpark_pandas() without explicitly initializing Snowpark pandas.
+
+import pytest
+
+from snowflake.snowpark._internal.utils import TempObjectType
+from tests.utils import Utils
+
+
+@pytest.fixture(scope="module")
+def tmp_table_basic(session):
+    table_name = Utils.random_name_for_temp_object(TempObjectType.TABLE)
+    Utils.create_table(
+        session, table_name, "id integer, foot_size float, shoe_model varchar"
+    )
+    session.sql(f"insert into {table_name} values (1, 32.0, 'medium')").collect()
+    session.sql(f"insert into {table_name} values (2, 27.0, 'small')").collect()
+    session.sql(f"insert into {table_name} values (3, 40.0, 'large')").collect()
+
+    try:
+        yield table_name
+    finally:
+        Utils.drop_table(session, table_name)
+
+
+def test_to_snowpark_pandas_no_modin(session, tmp_table_basic):
+    snowpark_df = session.table(tmp_table_basic)
+    # Check if modin is installed
+    try:
+        import modin  # noqa: F401
+
+        snowpark_df.to_snowpark_pandas()  # should have no errors
+    except ModuleNotFoundError:
+        with pytest.raises(ModuleNotFoundError, match="Modin is not installed."):
+            snowpark_df.to_snowpark_pandas()