100 coverage generic dataset

Signed-off-by: wmoreiraa <walber3@gmail.com>

kedro-datasets/kedro_datasets/polars/generic_dataset.py

@@ -172,7 +172,7 @@ def _assert_write_mode(self) -> None:
         """Check that the write mode is supported."""
         if self._write_mode not in ("overwrite", "ignore"):
             raise DataSetError(
-                f"Write mode {self._write_mode} not supported. "
+                f"Write mode `{self._write_mode}` is not supported. "
                 "Allowed values are: overwrite, ignore."
             )
 
@@ -181,11 +181,14 @@ def _ensure_file_system_target(self) -> None:
 
         if self._file_format not in ACCEPTED_READ_FILE_FORMATS:
             raise DataSetError(
-                f"Cannot create a dataset of file_format '{self._file_format}' as it "
-                f"does not support a filepath target/source."
+                f"Unable to retrieve 'polars.read_{self._file_format}' method, please"
+                " ensure that your "
+                "'file_format' parameter has been defined correctly as per the Polars"
+                " API"
+                " https://pola-rs.github.io/polars/py-polars/html/reference/io.html"
             )
 
-    def _load(self) -> pl.DataFrame:
+    def _load(self) -> pl.DataFrame:  # pylint: disable= inconsistent-return-statements
 
         self._ensure_file_system_target()
 
@@ -194,11 +197,6 @@ def _load(self) -> pl.DataFrame:
         if load_method:
             with self._fs.open(load_path, **self._fs_open_args_load) as fs_file:
                 return load_method(fs_file, **self._load_args)
-        raise DataSetError(
-            f"Unable to retrieve 'polars.read_{self._file_format}' method, please ensure that your "
-            "'file_format' parameter has been defined correctly as per the Polars API "
-            "https://pola-rs.github.io/polars/py-polars/html/reference/io.html"
-        )
 
     def _save(self, data: pl.DataFrame) -> None:
         if (
@@ -230,13 +228,6 @@ def _save(self, data: pl.DataFrame) -> None:
             with self._fs.open(save_path, **self._fs_open_args_save) as fs_file:
                 fs_file.write(buf.getvalue())
                 self._invalidate_cache()
-        else:
-            raise DataSetError(
-                f"Unable to retrieve 'polars.DataFrame.write_{self._file_format}' method, please "
-                "ensure that your 'file_format' parameter has been defined correctly as "
-                "per the Polars API "
-                "https://pola-rs.github.io/polars/py-polars/html/reference/io.html"
-            )
 
     def _exists(self) -> bool:
         try:

kedro-datasets/tests/polars/test_generic_dataset.py

@@ -79,6 +79,18 @@ def filepath_excel(tmp_path):
     return tmp_path / "test.xlsx"
 
 
+@pytest.fixture
+def parquet_data_set_ignore(dummy_dataframe: pl.DataFrame, filepath_parquet):
+    dummy_dataframe.write_parquet(filepath_parquet)
+
+    return GenericDataSet(
+        filepath=filepath_parquet.as_posix(),
+        file_format="parquet",
+        write_mode="ignore",
+        load_args={"low_memory": True},
+    )
+
+
 @pytest.fixture
 def excel_data_set_ignore(dummy_dataframe: pl.DataFrame, filepath_excel):
     pd_df = dummy_dataframe.to_pandas()
@@ -97,13 +109,23 @@ def excel_data_set_overwrite(dummy_dataframe: pl.DataFrame, filepath_excel):
     pd_df.to_excel(filepath_excel, index=False)
 
     return GenericDataSet(
-        filepath=filepath_excel.as_posix(),
-        file_format="excel",
-        write_mode="overwrite",
+        filepath=filepath_excel.as_posix(), file_format="excel", write_mode="overwrite"
     )
 
 
 class TestGenericExcelDataSet:
+    def test_assert_write_mode(self):
+        pattern = (
+            "Write mode `test` is not supported. "
+            "Allowed values are: overwrite, ignore."
+        )
+        with pytest.raises(DataSetError, match=pattern):
+            GenericDataSet(
+                filepath="test.xlsx",
+                file_format="excel",
+                write_mode="test",
+            )
+
     def test_load(self, excel_data_set_ignore):
         df = excel_data_set_ignore.load()
         assert df.shape == (2, 3)
@@ -161,6 +183,10 @@ def test_catalog_release(self, mocker):
 
 
 class TestGenericParquetDataSetVersioned:
+    def test_load_args(self, parquet_data_set_ignore):
+        df = parquet_data_set_ignore.load()
+        assert df.shape == (2, 3)
+
     def test_save_and_load(self, versioned_parquet_data_set, dummy_dataframe):
         """Test saving and reloading the data set."""
         versioned_parquet_data_set.save(dummy_dataframe)
@@ -517,18 +543,18 @@ def test_bad_file_format_argument(self):
         ds = GenericDataSet(filepath="test.kedro", file_format="kedro")
 
         pattern = (
-            "Cannot create a dataset of file_format 'kedro' as"
-            " it does not support a filepath target/source."
+            "Unable to retrieve 'polars.DataFrame.write_kedro' method, please "
+            "ensure that your 'file_format' parameter has been defined correctly as "
+            "per the Polars API "
+            "https://pola-rs.github.io/polars/py-polars/html/reference/io.html"
         )
-
         with pytest.raises(DataSetError, match=pattern):
-            _ = ds.load()
+            ds.save(pd.DataFrame([1]))
 
         pattern2 = (
-            "Unable to retrieve 'polars.DataFrame.write_kedro' method, please "
-            "ensure that your 'file_format' parameter has been defined correctly as "
-            "per the Polars API "
+            "Unable to retrieve 'polars.read_kedro' method, please ensure that your "
+            "'file_format' parameter has been defined correctly as per the Polars API "
             "https://pola-rs.github.io/polars/py-polars/html/reference/io.html"
         )
         with pytest.raises(DataSetError, match=pattern2):
-            ds.save(pd.DataFrame([1]))
+            ds.load()