feat: Allow arguments of type pathlib.Path for file I/O methods (#228)

Closes #146 .

### Summary of Changes

Changed type hints and docstrings for
* `Table.from_csv_file`
* `Table.to_csv_file`
* `Table.from_json_file`
* `Table.to_json_file`
* `Image.from_jpeg_file`
* `Image.to_jpeg_file`
* `Image.from_png_file`
* `Image.to_png_file`
* `resolve_resource_path`

to also accept arguments with type `Path`.

Updated tests accordingly.

---------

Co-authored-by: robmeth <91134475+robmeth@users.noreply.github.com>
Co-authored-by: zzril <>
Co-authored-by: megalinter-bot <129584137+megalinter-bot@users.noreply.github.com>
Co-authored-by: Lars Reimann <mail@larsreimann.com>

src/safeds/data/image/containers/_image.py

@@ -21,13 +21,13 @@ class Image:
     """
 
     @staticmethod
-    def from_jpeg_file(path: str) -> Image:
+    def from_jpeg_file(path: str | Path) -> Image:
         """
         Create an image from a JPEG file.
 
         Parameters
         ----------
-        path : str
+        path : str | Path
             The path to the JPEG file.
 
         Returns
@@ -41,13 +41,13 @@ def from_jpeg_file(path: str) -> Image:
         )
 
     @staticmethod
-    def from_png_file(path: str) -> Image:
+    def from_png_file(path: str | Path) -> Image:
         """
         Create an image from a PNG file.
 
         Parameters
         ----------
-        path : str
+        path : str | Path
             The path to the PNG file.
 
         Returns
@@ -86,25 +86,25 @@ def format(self) -> ImageFormat:
     # Conversion
     # ------------------------------------------------------------------------------------------------------------------
 
-    def to_jpeg_file(self, path: str) -> None:
+    def to_jpeg_file(self, path: str | Path) -> None:
         """
         Save the image as a JPEG file.
 
         Parameters
         ----------
-        path : str
+        path : str | Path
             The path to the JPEG file.
         """
         Path(path).parent.mkdir(parents=True, exist_ok=True)
         self._image.save(path, format="jpeg")
 
-    def to_png_file(self, path: str) -> None:
+    def to_png_file(self, path: str | Path) -> None:
         """
         Save the image as a PNG file.
 
         Parameters
         ----------
-        path : str
+        path : str | Path
             The path to the PNG file.
         """
         Path(path).parent.mkdir(parents=True, exist_ok=True)

src/safeds/data/tabular/containers/_table.py

@@ -60,13 +60,13 @@ class Table:
     # ------------------------------------------------------------------------------------------------------------------
 
     @staticmethod
-    def from_csv_file(path: str) -> Table:
+    def from_csv_file(path: str | Path) -> Table:
         """
         Read data from a CSV file into a table.
 
         Parameters
         ----------
-        path : str
+        path : str | Path
             The path to the CSV file.
 
         Returns
@@ -87,13 +87,13 @@ def from_csv_file(path: str) -> Table:
             raise FileNotFoundError(f'File "{path}" does not exist') from exception
 
     @staticmethod
-    def from_json_file(path: str) -> Table:
+    def from_json_file(path: str | Path) -> Table:
         """
         Read data from a JSON file into a table.
 
         Parameters
         ----------
-        path : str
+        path : str | Path
             The path to the JSON file.
 
         Returns
@@ -1200,7 +1200,7 @@ def plot_scatterplot(self, x_column_name: str, y_column_name: str) -> Image:
     # Conversion
     # ------------------------------------------------------------------------------------------------------------------
 
-    def to_csv_file(self, path: str) -> None:
+    def to_csv_file(self, path: str | Path) -> None:
         """
         Write the data from the table into a CSV file.
 
@@ -1209,15 +1209,15 @@ def to_csv_file(self, path: str) -> None:
 
         Parameters
         ----------
-        path : str
+        path : str | Path
             The path to the output file.
         """
         Path(path).parent.mkdir(parents=True, exist_ok=True)
         data_to_csv = self._data.copy()
         data_to_csv.columns = self._schema.column_names
         data_to_csv.to_csv(path, index=False)
 
-    def to_json_file(self, path: str) -> None:
+    def to_json_file(self, path: str | Path) -> None:
         """
         Write the data from the table into a JSON file.
 
@@ -1226,7 +1226,7 @@ def to_json_file(self, path: str) -> None:
 
         Parameters
         ----------
-        path : str
+        path : str | Path
             The path to the output file.
         """
         Path(path).parent.mkdir(parents=True, exist_ok=True)

tests/helpers/_resources.py

@@ -3,13 +3,13 @@
 _resources_root = Path(__file__).parent / ".." / "resources"
 
 
-def resolve_resource_path(resource_path: str) -> str:
+def resolve_resource_path(resource_path: str | Path) -> str:
     """
     Resolve a path relative to the `resources` directory to an absolute path.
 
     Parameters
     ----------
-    resource_path : str
+    resource_path : str | Path
         The path to the resource relative to the `resources` directory.
 
     Returns

tests/safeds/data/image/containers/test_image.py

@@ -11,33 +11,33 @@
 class TestFromJpegFile:
     @pytest.mark.parametrize(
         "path",
-        ["image/white_square.jpg"],
+        ["image/white_square.jpg", Path("image/white_square.jpg")],
     )
-    def test_should_load_jpeg_file(self, path: str) -> None:
+    def test_should_load_jpeg_file(self, path: str | Path) -> None:
         Image.from_jpeg_file(resolve_resource_path(path))
 
     @pytest.mark.parametrize(
         "path",
-        ["image/missing_file.jpg"],
+        ["image/missing_file.jpg", Path("image/missing_file.jpg")],
     )
-    def test_should_raise_if_file_not_found(self, path: str) -> None:
+    def test_should_raise_if_file_not_found(self, path: str | Path) -> None:
         with pytest.raises(FileNotFoundError):
             Image.from_jpeg_file(resolve_resource_path(path))
 
 
 class TestFromPngFile:
     @pytest.mark.parametrize(
         "path",
-        ["image/white_square.png"],
+        ["image/white_square.png", Path("image/white_square.png")],
     )
-    def test_should_load_png_file(self, path: str) -> None:
+    def test_should_load_png_file(self, path: str | Path) -> None:
         Image.from_png_file(resolve_resource_path(path))
 
     @pytest.mark.parametrize(
         "path",
-        ["image/missing_file.png"],
+        ["image/missing_file.png", Path("image/missing_file.png")],
     )
-    def test_should_raise_if_file_not_found(self, path: str) -> None:
+    def test_should_raise_if_file_not_found(self, path: str | Path) -> None:
         with pytest.raises(FileNotFoundError):
             Image.from_png_file(resolve_resource_path(path))
 
@@ -59,7 +59,7 @@ class TestToJpegFile:
         "path",
         ["image/white_square.jpg"],
     )
-    def test_should_save_jpeg_file(self, path: str) -> None:
+    def test_should_save_jpeg_file_by_str(self, path: str) -> None:
         image = Image.from_jpeg_file(resolve_resource_path(path))
 
         with NamedTemporaryFile() as tmp_file:
@@ -71,13 +71,29 @@ def test_should_save_jpeg_file(self, path: str) -> None:
 
         assert image._image.tobytes() == image_read_back._image.tobytes()
 
+    @pytest.mark.parametrize(
+        "path",
+        ["image/white_square.jpg"],
+    )
+    def test_should_save_jpeg_file_by_path(self, path: str) -> None:
+        image = Image.from_jpeg_file(resolve_resource_path(path))
+
+        with NamedTemporaryFile() as tmp_file:
+            tmp_file.close()
+        with Path(tmp_file.name).open("wb") as tmp_write_file:
+            image.to_jpeg_file(Path(tmp_write_file.name))
+        with Path(tmp_file.name).open("rb") as tmp_read_file:
+            image_read_back = Image.from_jpeg_file(tmp_read_file.name)
+
+        assert image._image.tobytes() == image_read_back._image.tobytes()
+
 
 class TestToPngFile:
     @pytest.mark.parametrize(
         "path",
         ["image/white_square.png"],
     )
-    def test_should_save_png_file(self, path: str) -> None:
+    def test_should_save_png_file_by_str(self, path: str) -> None:
         image = Image.from_png_file(resolve_resource_path(path))
 
         with NamedTemporaryFile() as tmp_file:
@@ -89,6 +105,22 @@ def test_should_save_png_file(self, path: str) -> None:
 
         assert image._image.tobytes() == image_read_back._image.tobytes()
 
+    @pytest.mark.parametrize(
+        "path",
+        ["image/white_square.png"],
+    )
+    def test_should_save_png_file_by_path(self, path: str) -> None:
+        image = Image.from_png_file(resolve_resource_path(path))
+
+        with NamedTemporaryFile() as tmp_file:
+            tmp_file.close()
+        with Path(tmp_file.name).open("wb") as tmp_write_file:
+            image.to_png_file(Path(tmp_write_file.name))
+        with Path(tmp_file.name).open("rb") as tmp_read_file:
+            image_read_back = Image.from_png_file(tmp_read_file.name)
+
+        assert image._image.tobytes() == image_read_back._image.tobytes()
+
 
 class TestReprJpeg:
     @pytest.mark.parametrize(

tests/safeds/data/tabular/containers/_table/test_from_csv_file.py

@@ -1,15 +1,25 @@
+from pathlib import Path
+
 import pytest
 from safeds.data.tabular.containers import Table
 
 from tests.helpers import resolve_resource_path
 
 
-def test_from_csv_file_valid() -> None:
-    table = Table.from_csv_file(resolve_resource_path("table.csv"))
+@pytest.mark.parametrize(
+    "path",
+    ["table.csv", Path("table.csv")],
+)
+def test_from_csv_file_valid(path: str | Path) -> None:
+    table = Table.from_csv_file(resolve_resource_path(path))
     assert table.get_column("A").get_value(0) == 1
     assert table.get_column("B").get_value(0) == 2
 
 
-def test_from_csv_file_invalid() -> None:
+@pytest.mark.parametrize(
+    "path",
+    ["test_table_from_csv_file_invalid.csv", Path("test_table_from_csv_file_invalid.csv")],
+)
+def test_from_csv_file_invalid(path: str | Path) -> None:
     with pytest.raises(FileNotFoundError):
-        Table.from_csv_file(resolve_resource_path("test_table_from_csv_file_invalid.csv"))
+        Table.from_csv_file(resolve_resource_path(path))

tests/safeds/data/tabular/containers/_table/test_from_json_file.py

@@ -1,15 +1,25 @@
+from pathlib import Path
+
 import pytest
 from safeds.data.tabular.containers import Table
 
 from tests.helpers import resolve_resource_path
 
 
-def test_from_json_file_valid() -> None:
-    table = Table.from_json_file(resolve_resource_path("table.json"))
+@pytest.mark.parametrize(
+    "path",
+    ["table.json", Path("table.json")],
+)
+def test_from_json_file_valid(path: str | Path) -> None:
+    table = Table.from_json_file(resolve_resource_path(path))
     assert table.get_column("A").get_value(0) == 1
     assert table.get_column("B").get_value(0) == 2
 
 
-def test_from_json_file_invalid() -> None:
+@pytest.mark.parametrize(
+    "path",
+    ["test_table_from_json_file_invalid.json", Path("test_table_from_json_file_invalid.json")],
+)
+def test_from_json_file_invalid(path: str | Path) -> None:
     with pytest.raises(FileNotFoundError):
-        Table.from_json_file(resolve_resource_path("test_table_from_json_file_invalid.json"))
+        Table.from_json_file(resolve_resource_path(path))

tests/safeds/data/tabular/containers/_table/test_to_csv_file.py

@@ -4,7 +4,7 @@
 from safeds.data.tabular.containers import Table
 
 
-def test_to_csv_file() -> None:
+def test_to_csv_file_by_str() -> None:
     table = Table.from_dict({"col1": ["col1_1"], "col2": ["col2_1"]})
     with NamedTemporaryFile() as tmp_table_file:
         tmp_table_file.close()
@@ -13,3 +13,14 @@ def test_to_csv_file() -> None:
         with Path(tmp_table_file.name).open("r", encoding="utf-8") as tmp_file:
             table_r = Table.from_csv_file(tmp_file.name)
     assert table == table_r
+
+
+def test_to_csv_file_by_path() -> None:
+    table = Table.from_dict({"col1": ["col1_1"], "col2": ["col2_1"]})
+    with NamedTemporaryFile() as tmp_table_file:
+        tmp_table_file.close()
+        with Path(tmp_table_file.name).open("w", encoding="utf-8") as tmp_file:
+            table.to_csv_file(Path(tmp_file.name))
+        with Path(tmp_table_file.name).open("r", encoding="utf-8") as tmp_file:
+            table_r = Table.from_csv_file(Path(tmp_file.name))
+    assert table == table_r

tests/safeds/data/tabular/containers/_table/test_to_json_file.py

@@ -4,7 +4,7 @@
 from safeds.data.tabular.containers import Table
 
 
-def test_to_json_file() -> None:
+def test_to_json_file_by_str() -> None:
     table = Table.from_dict({"col1": ["col1_1"], "col2": ["col2_1"]})
     with NamedTemporaryFile() as tmp_table_file:
         tmp_table_file.close()
@@ -13,3 +13,14 @@ def test_to_json_file() -> None:
         with Path(tmp_table_file.name).open("r", encoding="utf-8") as tmp_file:
             table_r = Table.from_json_file(tmp_file.name)
     assert table == table_r
+
+
+def test_to_json_file_by_path() -> None:
+    table = Table.from_dict({"col1": ["col1_1"], "col2": ["col2_1"]})
+    with NamedTemporaryFile() as tmp_table_file:
+        tmp_table_file.close()
+        with Path(tmp_table_file.name).open("w", encoding="utf-8") as tmp_file:
+            table.to_json_file(Path(tmp_file.name))
+        with Path(tmp_table_file.name).open("r", encoding="utf-8") as tmp_file:
+            table_r = Table.from_json_file(Path(tmp_file.name))
+    assert table == table_r