diff --git a/phlop/reflection.py b/phlop/reflection.py
index e0d6bcb..7526ced 100644
--- a/phlop/reflection.py
+++ b/phlop/reflection.py
@@ -12,9 +12,14 @@
 
 from phlop.sys import extend_sys_path
 
+FORCE_RAISE_ON_IMPORT_ERROR = os.getenv(
+    "PHLOP_FORCE_RAISE_ON_IMPORT_ERROR", "False"
+).lower() in ("true", "1", "t")
 
-def classes_in_file(file, subclasses_only=None, fail_on_import_error=True):
-    assert file
+
+def classes_in_file(file_path, subclasses_only=None, fail_on_import_error=False):
+    file = Path(file_path)
+    assert file.exists()
     module = str(file).replace(os.path.sep, ".")[:-3]
     assert module
 
@@ -23,7 +28,7 @@ def classes_in_file(file, subclasses_only=None, fail_on_import_error=True):
 
     classes = []
 
-    with extend_sys_path(os.getcwd()):
+    with extend_sys_path([os.getcwd(), str(file.parent)]):
         try:
             for name, cls in inspect.getmembers(
                 importlib.import_module(module), inspect.isclass
@@ -34,7 +39,7 @@ def classes_in_file(file, subclasses_only=None, fail_on_import_error=True):
                 if should_add:
                     classes += [cls]
         except (ValueError, ModuleNotFoundError) as e:
-            if fail_on_import_error:
+            if fail_on_import_error or FORCE_RAISE_ON_IMPORT_ERROR:
                 raise e
             logging.error(f"Skipping on error: {e} in module {module}")
 
diff --git a/phlop/run/test_cases.py b/phlop/run/test_cases.py
index ef2fd08..3f620b6 100644
--- a/phlop/run/test_cases.py
+++ b/phlop/run/test_cases.py
@@ -7,8 +7,8 @@
 
 import logging
 import multiprocessing
-import sys
 import re
+import sys
 import unittest
 from pathlib import Path
 
diff --git a/pyproject.toml b/pyproject.toml
index 1e4eede..cd310e6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [project]
 name = "phlop"
-version = "0.0.14"
+version = "0.0.15"
 
 dependencies = [
 
@@ -21,6 +21,12 @@ classifiers = [
 
 [build-system]
 requires = [
-    "setuptools>=42", "wheel", "packaging", "dill"
+    "setuptools>=62", "wheel", "packaging", "dill"
 ]
 
+[tool.setuptools]
+include-package-data = false
+
+[tool.setuptools.packages.find]
+include = ["/phlop*"]
+exclude = ["/sh*", "/tests*"]
diff --git a/setup.py b/setup.py
deleted file mode 100644
index 602dc1f..0000000
--- a/setup.py
+++ /dev/null
@@ -1,10 +0,0 @@
-from setuptools import find_packages, setup
-
-setup(
-    name="phlop",
-    version="0.0.14",
-    cmdclass={},
-    classifiers=[],
-    include_package_data=True,
-    packages=find_packages(exclude=["lib/", "tests/"]),
-)