Updated tests.

Fixed failing tests and added one for new method in print.py.

Author: sbyrne-sf

tests/io/writer/test_print.py

@@ -29,12 +29,18 @@ def print_writer(self, mock_spark_session):
 
     def test_write_to_dlo(self, print_writer, mock_dataframe):
         """Test write_to_dlo method calls dataframe.show()."""
+        # Mock the validate_dataframe_columns_against_dlo method
+        print_writer.validate_dataframe_columns_against_dlo = MagicMock()
+
         # Call the method
         print_writer.write_to_dlo("test_dlo", mock_dataframe, WriteMode.OVERWRITE)
 
         # Verify show() was called
         mock_dataframe.show.assert_called_once()
 
+        # Verify validate_dataframe_columns_against_dlo was called
+        print_writer.validate_dataframe_columns_against_dlo.assert_called_once()
+
     def test_write_to_dmo(self, print_writer, mock_dataframe):
         """Test write_to_dmo method calls dataframe.show()."""
         # Call the method
@@ -59,9 +65,37 @@ def test_ignores_name_and_write_mode(self, print_writer, mock_dataframe):
         for name, write_mode in test_cases:
             # Reset mock before each call
             mock_dataframe.show.reset_mock()
-
+            # Mock the validate_dataframe_columns_against_dlo method
+            print_writer.validate_dataframe_columns_against_dlo = MagicMock()
             # Call method
             print_writer.write_to_dlo(name, mock_dataframe, write_mode)
 
             # Verify show() was called with no arguments
             mock_dataframe.show.assert_called_once_with()
+
+            print_writer.validate_dataframe_columns_against_dlo.assert_called_once()
+
+    def test_validate_dataframe_columns_against_dlo(self, print_writer, mock_dataframe):
+        """Test validate_dataframe_columns_against_dlo method."""
+        # Mock the QueryAPIDataCloudReader
+        mock_reader = MagicMock()
+        mock_dlo_df = MagicMock()
+        mock_dlo_df.columns = ["col1", "col2"]
+        mock_reader.read_dlo.return_value = mock_dlo_df
+
+        # Set up mock dataframe columns
+        mock_dataframe.columns = ["col1", "col2", "col3"]
+
+        # Test that validation raises ValueError for extra columns
+        with pytest.raises(ValueError) as exc_info:
+            print_writer.validate_dataframe_columns_against_dlo(
+                mock_dataframe, "test_dlo", mock_reader
+            )
+
+        assert "col3" in str(exc_info.value)
+
+        # Test successful validation with matching columns
+        mock_dataframe.columns = ["col1", "col2"]
+        print_writer.validate_dataframe_columns_against_dlo(
+            mock_dataframe, "test_dlo", mock_reader
+        )