tests: use updated conftest from pymplate, this allows to run individual test modules properly

e.g. pytest --pyargs my.core.tests.test_get_files

conftest.py

@@ -0,0 +1,47 @@
+# this is a hack to monkey patch pytest so it handles tests inside namespace packages without __init__.py properly
+# without it, pytest can't discover the package root for some reason
+# also see https://github.com/karlicoss/pytest_namespace_pkgs for more
+
+import os
+import pathlib
+from typing import Optional
+
+import _pytest.main
+import _pytest.pathlib
+
+# we consider all dirs in repo/ to be namespace packages
+root_dir = pathlib.Path(__file__).absolute().parent.resolve()  # / 'src'
+assert root_dir.exists(), root_dir
+
+# TODO assert it contains package name?? maybe get it via setuptools..
+
+namespace_pkg_dirs = [str(d) for d in root_dir.iterdir() if d.is_dir()]
+
+# resolve_package_path is called from _pytest.pathlib.import_path
+# takes a full abs path to the test file and needs to return the path to the 'root' package on the filesystem
+resolve_pkg_path_orig = _pytest.pathlib.resolve_package_path
+def resolve_package_path(path: pathlib.Path) -> Optional[pathlib.Path]:
+    result = path  # search from the test file upwards
+    for parent in result.parents:
+        if str(parent) in namespace_pkg_dirs:
+            return parent
+    if os.name == 'nt':
+        # ??? for some reason on windows it is trying to call this against conftest? but not on linux/osx
+        if path.name == 'conftest.py':
+            return resolve_pkg_path_orig(path)
+    raise RuntimeError("Couldn't determine path for ", path)
+_pytest.pathlib.resolve_package_path = resolve_package_path
+
+
+# without patching, the orig function returns just a package name for some reason
+# (I think it's used as a sort of fallback)
+# so we need to point it at the absolute path properly
+# not sure what are the consequences.. maybe it wouldn't be able to run against installed packages? not sure..
+search_pypath_orig = _pytest.main.search_pypath
+def search_pypath(module_name: str) -> str:
+    mpath = root_dir / module_name.replace('.', os.sep)
+    if not mpath.is_dir():
+        mpath = mpath.with_suffix('.py')
+        assert mpath.exists(), mpath  # just in case
+    return str(mpath)
+_pytest.main.search_pypath = search_pypath

my/core/tests/test_get_files.py

@@ -175,12 +175,17 @@ TMP = tempfile.gettempdir()
 test_path = Path(TMP) / 'hpi_test'
 
 
-def setup():
+@pytest.fixture(autouse=True)
+def prepare():
     teardown()
     test_path.mkdir()
+    try:
+        yield
+    finally:
+        teardown()
 
 
-def teardown():
+def teardown() -> None:
     if test_path.is_dir():
         shutil.rmtree(test_path)