Index: flake8_pyi-23.11.0/tests/test_pyi_files.py
===================================================================
--- flake8_pyi-23.11.0.orig/tests/test_pyi_files.py
+++ flake8_pyi-23.11.0/tests/test_pyi_files.py
@@ -43,6 +43,9 @@ def test_pyi_file(path: str) -> None:
         option = flag.split("=")[0]
         assert option not in {"--ignore", "--select"}, bad_flag_msg(option[2:])
 
+    pythonpath = os.environ.get("PYTHONPATH")
+    pythonpath = f"PYTHONPATH={pythonpath}:."
+
     # Silence DeprecationWarnings from our dependencies (pyflakes, flake8-bugbear, etc.)
     #
     # For DeprecationWarnings coming from flake8-pyi itself,
@@ -51,6 +54,8 @@ def test_pyi_file(path: str) -> None:
     # but the test failure report that pytest gives is much easier to read
     # if we use `-Wdefault:::pyi`
     flake8_invocation = [
+        "env",
+        pythonpath,
         sys.executable,
         "-Wignore",
         "-Wdefault:::pyi",