--- a/tests/test_helper.py
+++ b/tests/test_helper.py
@@ -269,9 +269,9 @@
     print("subprocess:", " ".join(cmd))  # very useful on failure
     env = {
         # We may need to find nanoemoji and other pip-installed cli tools
-        "PATH": str(Path(shutil.which("nanoemoji")).parent),
+        "PATH": str(Path(shutil.which("nanoemoji")).parent) + ":" + os.environ["PATH"],
         # We may need to find test modules
-        "PYTHONPATH": os.pathsep.join((str(Path(__file__).parent),)),
+        "PYTHONPATH": os.pathsep.join((str(Path(__file__).parent),)) + ":" + os.environ["PYTHONPATH"],
     }
     # Needed for windows CI to function; ref https://github.com/appveyor/ci/issues/1995
     if "SYSTEMROOT" in os.environ: