diff --git a/setup/test.py b/setup/test.py
index 2a4d93d290..50d875053e 100644
--- a/setup/test.py
+++ b/setup/test.py
@@ -54,8 +54,7 @@ class Test(BaseTest):
         import warnings
         warnings.filterwarnings('ignore', message="'cgi' is deprecated and slated for removal in Python 3.13")
 
-        if is_ci:
-            SW = os.environ['SW']
+        if is_ci and (SW := os.environ.get('SW')):
             if ismacos:
                 import ctypes
                 sys.libxml2_dylib = ctypes.CDLL(os.path.join(SW, 'lib', 'libxml2.dylib'))