diff --git a/tests/auto/widgets/proxypac/tst_proxypac.cpp b/tests/auto/widgets/proxypac/tst_proxypac.cpp
index f9340341b39786b56926671bca341f014a290bce..934e23fdea45d10969165cb55640147f38d17411 100644
--- a/tests/auto/widgets/proxypac/tst_proxypac.cpp
+++ b/tests/auto/widgets/proxypac/tst_proxypac.cpp
@@ -46,6 +46,10 @@ private slots:
 
 void tst_ProxyPac::proxypac()
 {
+    const QString fromEnv = QString::fromLocal8Bit(qgetenv("QTWEBENGINE_CHROMIUM_FLAGS"));
+    if (!fromEnv.contains("--proxy-pac-url"))
+        qFatal("--proxy-pac-url argument is not passed.");
+
     ProxyServer proxyServer1;
     proxyServer1.setPort(5551);
     proxyServer1.run();