diff --git a/test.sh b/test.sh
index d3f07befe..574b5cdda 100755
--- a/test.sh
+++ b/test.sh
@@ -69,6 +69,11 @@ for name in SystemRoot SYSTEMROOT WINDIR COMSPEC PATHEXT; do
 	[[ -z "$value" ]] || test_env+=("$name=$value")
 done
 
+# Trust extra certificates of proxies that inspect HTTPS (corporate proxies, sandboxes).
+# Network tests fail with self-signed certificate errors without it.
+value="${NODE_EXTRA_CA_CERTS-}"
+[[ -z "$value" ]] || test_env+=("NODE_EXTRA_CA_CERTS=$value")
+
 # Preserve CI detection only for runner behavior and test reporting.
 for name in CI GITHUB_ACTIONS; do
 	value="${!name-}"