More tests.

Author: tobiasraabe

src/_pytask/nodes.py

@@ -31,6 +31,7 @@ class ProductType:
 
 
 Product = ProductType()
+"""ProductType: A singleton to mark products in annotations."""
 
 
 @define(kw_only=True)
@@ -84,7 +85,8 @@ def execute(self, **kwargs: Any) -> None:
             if not structure_out == structure_return:
                 raise ValueError(
                     "The structure of the function return does not match the structure "
-                    "of the return annotation."
+                    f"of the return annotation.\n\nFunction return: {structure_out}\n\n"
+                    f"Return annotation: {structure_return}"
                 )
 
             for out_, return_ in zip(
@@ -142,6 +144,7 @@ def state(self) -> str | None:
         return None
 
     def load(self) -> Path:
+        """Load the value."""
         return self.value
 
     def save(self, value: bytes | str) -> None:
@@ -168,12 +171,15 @@ class PythonNode(Node):
     """Whether the value should be hashed to determine the state."""
 
     def load(self) -> Any:
+        """Load the value."""
         return self.value
 
     def save(self, value: Any) -> NoReturn:
+        """Save the value."""
         raise NotImplementedError
 
     def from_annot(self, value: Any) -> None:
+        """Set the value from a function annotation."""
         self.value = value
 
     def state(self) -> str | None:

tests/test_execute.py

@@ -555,9 +555,7 @@ def test_return_with_path_annotation_as_return(runner, tmp_path):
     from typing_extensions import Annotated
     from pytask import PathNode
 
-    path = Path(__file__).parent.joinpath("file.txt")
-
-    def task_example() -> Annotated[str, path]:
+    def task_example() -> Annotated[str, Path("file.txt")]:
         return "Hello, World!"
     """
     tmp_path.joinpath("task_module.py").write_text(textwrap.dedent(source))
@@ -647,3 +645,24 @@ def task_example() -> Annotated[int, node]:
 
     data = pickle.loads(tmp_path.joinpath("data.pkl").read_bytes())  # noqa: S301
     assert data == 1
+
+
+@pytest.mark.end_to_end()
+def test_error_when_return_pytree_mismatch(runner, tmp_path):
+    source = """
+    from pathlib import Path
+    from typing import Any
+    from typing_extensions import Annotated
+    from pytask import PathNode
+
+    node1 = PathNode.from_path(Path(__file__).parent.joinpath("file1.txt"))
+    node2 = PathNode.from_path(Path(__file__).parent.joinpath("file2.txt"))
+
+    def task_example() -> Annotated[str, (node1, node2)]:
+        return "Hello,"
+    """
+    tmp_path.joinpath("task_module.py").write_text(textwrap.dedent(source))
+    result = runner.invoke(cli, [tmp_path.as_posix()])
+    assert result.exit_code == ExitCode.FAILED
+    assert "Function return: PyTreeSpec(*, NoneIsLeaf)" in result.output
+    assert "Return annotation: PyTreeSpec((*, *), NoneIsLeaf)" in result.output