Fix tests.

Author: tobiasraabe

CHANGES.md

@@ -5,7 +5,12 @@ chronological order. Releases follow [semantic versioning](https://semver.org/)
 releases are available on [PyPI](https://pypi.org/project/pytask-parallel) and
 [Anaconda.org](https://anaconda.org/conda-forge/pytask-parallel).
 
-## 0.2.0 - 2022-xx-xx
+## 0.2.1 - 2022-08-xx
+
+- {pull}`43` adds docformatter.
+- {pull}`44` allows to capture warnings from subprocesses. Fixes {issue}`41`.
+
+## 0.2.0 - 2022-04-15
 
 - {pull}`31` adds types to the package.
 - {pull}`36` adds a test for <https://github.com/pytask-dev/pytask/issues/216>.

src/pytask_parallel/execute.py

@@ -280,7 +280,7 @@ def pytask_execute_task(session: Session, task: Task) -> Future[Any] | None:
 
 def _mock_processes_for_threads(
     func: Callable[..., Any], **kwargs: Any
-) -> tuple[list[Any], None]:
+) -> tuple[list[Any], tuple[type[BaseException], BaseException, TracebackType] | None]:
     """Mock execution function such that it returns the same as for processes.
 
     The function for processes returns ``warning_reports`` and an ``exception``. With
@@ -289,8 +289,13 @@ def _mock_processes_for_threads(
 
     """
     __tracebackhide__ = True
-    func(**kwargs)
-    return [], None
+    try:
+        func(**kwargs)
+    except Exception:
+        exc_info = sys.exc_info()
+    else:
+        exc_info = None
+    return [], exc_info
 
 
 def _create_kwargs_for_task(task: Task) -> dict[Any, Any]:

tests/test_execute.py

@@ -294,7 +294,11 @@ def task_example(produces):
 
 
 @pytest.mark.end_to_end
-@pytest.mark.parametrize("parallel_backend", PARALLEL_BACKENDS)
+@pytest.mark.parametrize(
+    "parallel_backend",
+    # Capturing warnings is not thread-safe.
+    [backend for backend in PARALLEL_BACKENDS if backend != "threads"],
+)
 def test_collect_warnings_from_parallelized_tasks(runner, tmp_path, parallel_backend):
     source = """
     import pytask