allow optional arguments in load()

CHANGELOG.md

@@ -10,14 +10,15 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 Anything MAY change at any time. The public API SHOULD NOT be considered stable.").
 While in this phase, we will denote breaking changes with a minor increase.
 
-## Unreleased patch
+## 0.4.0
 
 ### Changed
 
+* The `load` function in `load.py` can contain optional arguments. Previously no arguments were allowed.
+* `load.py` and `schema.py` are publicly accessible under `dac_pkg_name.load` and `dac_pkg_name.schema` respectively. Previously they were marked as private modules, under `dac_pkg_name._load` and `dac_pkg_name._schema`.
+* `Schema` does not have to be a `pandera.DataFrameModel` anymore, but any class that implements a `validate` method (see the `_input.interface.Validator` protocol).
 * `dac` does not rely on [`pydantic`](https://pypi.org/project/pydantic/) anymore, and uses [`dataclass`](https://docs.python.org/3/library/dataclasses.html#) instead.
   Changes affect `PackConfig` and `PyProjectConfig`.
-* `Schema` does not have to be a `pandera.DataFrameModel` anymore, but any class that implements a `validate` method (see the `_input.interface.Validator` protocol).
-* `load.py` and `schema.py` are publicly accessible under `dac_pkg_name.load` and `dac_pkg_name.schema` respectively. Previously they were marked as private modules, under `dac_pkg_name._load` and `dac_pkg_name._schema`.
 
 ## 0.3.3
 

src/dac/_input/config.py

@@ -45,7 +45,7 @@ def _check_load_contains_expected_function(self) -> None:
 
         try:
             signature = inspect.getfullargspec(pkg.load)
-            assert signature.args == []
+            assert len(signature.args) == (len(signature.defaults) if signature.defaults is not None else 0)
         except Exception as e:
             raise ValueError((f"{self.load_path.as_posix()} does not contain the required `def load()`")) from e
 

test/data/__init__.py

@@ -17,6 +17,14 @@ def get_path_to_sample_load_parquet_as_pandas() -> Path:
     return Path(__file__).parent / "load/parquet_as_pandas.py"
 
 
+def get_path_to_sample_load_parquet_as_pandas_with_sample_frac() -> Path:
+    return Path(__file__).parent / "load/parquet_as_pandas_with_sample_frac.py"
+
+
+def get_path_to_sample_load_parquet_as_pandas_with_sample_n() -> Path:
+    return Path(__file__).parent / "load/parquet_as_pandas_with_sample_n.py"
+
+
 def get_path_to_self_contained_load_as_pandas() -> Path:
     return Path(__file__).parent / "load/self_contained_as_pandas.py"
 

test/data/load/parquet_as_pandas_with_sample_frac.py

@@ -0,0 +1,7 @@
+from pathlib import Path
+
+import pandas as pd
+
+
+def load(sample_frac: float = 1.0) -> pd.DataFrame:
+    return pd.read_parquet(Path(__file__).parent / "sample.parquet").sample(frac=sample_frac)

test/data/load/parquet_as_pandas_with_sample_n.py

@@ -0,0 +1,7 @@
+from pathlib import Path
+
+import pandas as pd
+
+
+def load(sample_n: int) -> pd.DataFrame:
+    return pd.read_parquet(Path(__file__).parent / "sample.parquet").sample(n=sample_n)

test/unit_test/_input/config_test.py

@@ -4,6 +4,8 @@
     get_path_to_invalid_load,
     get_path_to_invalid_schema,
     get_path_to_sample_load_parquet_as_pandas,
+    get_path_to_sample_load_parquet_as_pandas_with_sample_frac,
+    get_path_to_sample_load_parquet_as_pandas_with_sample_n,
     get_path_to_sample_parquet,
     get_path_to_sample_schema,
     get_path_to_schema_incompatible_with_sample_df,
@@ -75,6 +77,29 @@ def test_if_load_does_not_contain_expected_function_then_raise_exception(pyproje
             )
 
 
+def test_if_load_contain_optional_arguments_then_do_not_raise_exception(pyproject: PyProjectConfig):
+    with TemporaryDirectory() as tmp_dir:
+        PackConfig(
+            data_path=get_path_to_sample_parquet(),
+            load_path=get_path_to_sample_load_parquet_as_pandas_with_sample_frac(),
+            schema_path=get_path_to_sample_schema(),
+            wheel_dir=Path(tmp_dir),
+            pyproject=pyproject,
+        )
+
+
+def test_if_load_contain_non_optional_arguments_then_raise_exception(pyproject: PyProjectConfig):
+    with TemporaryDirectory() as tmp_dir:
+        with pytest.raises(ValueError):
+            PackConfig(
+                data_path=get_path_to_sample_parquet(),
+                load_path=get_path_to_sample_load_parquet_as_pandas_with_sample_n(),
+                schema_path=get_path_to_sample_schema(),
+                wheel_dir=Path(tmp_dir),
+                pyproject=pyproject,
+            )
+
+
 def test_if_invalid_schema_path_then_raise_exception(pyproject: PyProjectConfig):
     with TemporaryDirectory() as tmp_dir:
         with pytest.raises(ValueError):