[FEAT] connect: Add support for select

tests/connect/test_select.py

@@ -0,0 +1,20 @@
+from __future__ import annotations
+
+from pyspark.sql.functions import col
+
+
+def test_select(spark_session):
+    # Create DataFrame from range(10)
+    df = spark_session.range(10)
+
+    # Select just the 'id' column
+    df_selected = df.select(col("id"))
+
+    # Verify the schema is unchanged since we selected same column
+    assert df_selected.schema == df.schema, "Schema should be unchanged after selecting same column"
+    assert len(df_selected.collect()) == 10, "Row count should be unchanged after select"
+
+    # Verify the data is unchanged
+    df_data = [row["id"] for row in df.collect()]
+    df_selected_data = [row["id"] for row in df_selected.collect()]
+    assert df_data == df_selected_data, "Data should be unchanged after select"