add tests for polars decorators (#1615)

Signed-off-by: cosmicBboy <niels.bantilan@gmail.com>

pandera/decorators.py

@@ -27,17 +27,17 @@
 
 from pandera import errors
 from pandera.api.base.error_handler import ErrorHandler
-from pandera.api.pandas.array import SeriesSchema
-from pandera.api.pandas.container import DataFrameSchema
-from pandera.api.pandas.model import DataFrameModel
+from pandera.api.dataframe.components import ComponentSchema
+from pandera.api.dataframe.container import DataFrameSchema
+from pandera.api.dataframe.model import DataFrameModel
 from pandera.inspection_utils import (
     is_classmethod_from_meta,
     is_decorated_classmethod,
 )
 from pandera.typing import AnnotationInfo
 from pandera.validation_depth import validation_type
 
-Schemas = Union[DataFrameSchema, SeriesSchema]
+Schemas = Union[DataFrameSchema, ComponentSchema]
 InputGetter = Union[str, int]
 OutputGetter = Union[str, int, Callable]
 F = TypeVar("F", bound=Callable)
@@ -84,7 +84,7 @@ def _get_fn_argnames(fn: Callable) -> List[str]:
 def _handle_schema_error(
     decorator_name,
     fn: Callable,
-    schema: Union[DataFrameSchema, SeriesSchema],
+    schema: Union[DataFrameSchema, ComponentSchema],
     data_obj: Any,
     schema_error: errors.SchemaError,
 ) -> NoReturn:
@@ -110,7 +110,7 @@ def _handle_schema_error(
 def _parse_schema_error(
     decorator_name,
     fn: Callable,
-    schema: Union[DataFrameSchema, SeriesSchema],
+    schema: Union[DataFrameSchema, ComponentSchema],
     data_obj: Any,
     schema_error: errors.SchemaError,
     reason_code: errors.SchemaErrorReason,
@@ -355,7 +355,7 @@ def check_output(
     # pylint: disable=too-many-boolean-expressions
     if callable(obj_getter) and (
         schema.coerce
-        or (schema.index is not None and schema.index.coerce)
+        or (schema.index is not None and schema.index.coerce)  # type: ignore[union-attr]
         or (
             isinstance(schema, DataFrameSchema)
             and any(col.coerce for col in schema.columns.values())
@@ -490,7 +490,7 @@ def _wrapper(
         out_schemas = out
         if isinstance(out, list):
             out_schemas = out
-        elif isinstance(out, (DataFrameSchema, SeriesSchema)):
+        elif isinstance(out, (DataFrameSchema, ComponentSchema)):
             out_schemas = [(None, out)]  # type: ignore
         elif isinstance(out, tuple):
             out_schemas = [out]

pandera/typing/polars.py

@@ -35,6 +35,13 @@ class LazyFrame(DataFrameBase, pl.LazyFrame, Generic[T]):
         *new in 0.19.0*
         """
 
+    class DataFrame(DataFrameBase, pl.DataFrame, Generic[T]):
+        """
+        Pandera generic for pl.LazyFrame, only used for type annotation.
+
+        *new in 0.19.0*
+        """
+
     # pylint: disable=too-few-public-methods
     class Series(SeriesBase, pl.Series, Generic[T]):
         """

tests/polars/test_polars_decorators.py

@@ -0,0 +1,96 @@
+"""Unit tests for using schemas with polars and function decorators."""
+
+import polars as pl
+import pytest
+
+import pandera.polars as pa
+import pandera.typing.polars as pa_typing
+
+
+@pytest.fixture
+def data() -> pl.DataFrame:
+    return pl.DataFrame({"a": [1, 2, 3]})
+
+
+@pytest.fixture
+def invalid_data(data) -> pl.DataFrame:
+    return data.rename({"a": "b"})
+
+
+def test_polars_dataframe_check_io(data, invalid_data):
+    # pylint: disable=unused-argument
+
+    schema = pa.DataFrameSchema({"a": pa.Column(int)})
+
+    @pa.check_input(schema)
+    def fn_check_input(x):
+        ...
+
+    @pa.check_output(schema)
+    def fn_check_output(x):
+        return x
+
+    @pa.check_io(x=schema, out=schema)
+    def fn_check_io(x):
+        return x
+
+    @pa.check_io(x=schema, out=schema)
+    def fn_check_io_invalid(x):
+        return x.rename({"a": "b"})
+
+    # valid data should pass
+    fn_check_input(data)
+    fn_check_output(data)
+    fn_check_io(data)
+
+    # invalid data or invalid function should not pass
+    with pytest.raises(pa.errors.SchemaError):
+        fn_check_input(invalid_data)
+
+    with pytest.raises(pa.errors.SchemaError):
+        fn_check_output(invalid_data)
+
+    with pytest.raises(pa.errors.SchemaError):
+        fn_check_io_invalid(data)
+
+
+def test_polars_dataframe_check_types(data, invalid_data):
+    # pylint: disable=unused-argument
+
+    class Model(pa.DataFrameModel):
+        a: int
+
+    @pa.check_types
+    def fn_check_input(x: pa_typing.DataFrame[Model]):
+        ...
+
+    @pa.check_types
+    def fn_check_output(x) -> pa_typing.DataFrame[Model]:
+        return x
+
+    @pa.check_types
+    def fn_check_io(
+        x: pa_typing.DataFrame[Model],
+    ) -> pa_typing.DataFrame[Model]:
+        return x
+
+    @pa.check_types
+    def fn_check_io_invalid(
+        x: pa_typing.DataFrame[Model],
+    ) -> pa_typing.DataFrame[Model]:
+        return x.rename({"a": "b"})
+
+    # valid data should pass
+    fn_check_input(data)
+    fn_check_output(data)
+    fn_check_io(data)
+
+    # invalid data or invalid function should not pass
+    with pytest.raises(pa.errors.SchemaError):
+        fn_check_input(invalid_data)
+
+    with pytest.raises(pa.errors.SchemaError):
+        fn_check_output(invalid_data)
+
+    with pytest.raises(pa.errors.SchemaError):
+        fn_check_io_invalid(data)