diff --git a/mozilla/tools/test-harness/xpcshell-simple/test_all.sh b/mozilla/tools/test-harness/xpcshell-simple/test_all.sh
index f195c70f437..dddc18db041 100755
--- a/mozilla/tools/test-harness/xpcshell-simple/test_all.sh
+++ b/mozilla/tools/test-harness/xpcshell-simple/test_all.sh
@@ -44,7 +44,7 @@
 ulimit -c 20480 2> /dev/null
 
 # Make assertions fatal
-export XPCOM_DEBUG_BREAK=stack-and-abort
+XPCOM_DEBUG_BREAK=stack-and-abort; export XPCOM_DEBUG_BREAK
 
 exit_status=0
 
diff --git a/mozilla/tools/test-harness/xpcshell-simple/test_one.sh b/mozilla/tools/test-harness/xpcshell-simple/test_one.sh
index f895c8c309b..1902465cfd2 100755
--- a/mozilla/tools/test-harness/xpcshell-simple/test_one.sh
+++ b/mozilla/tools/test-harness/xpcshell-simple/test_one.sh
@@ -45,7 +45,7 @@
 ulimit -c 20480 2> /dev/null
 
 # Make assertions fatal
-export XPCOM_DEBUG_BREAK=stack-and-abort
+XPCOM_DEBUG_BREAK=stack-and-abort; export XPCOM_DEBUG_BREAK
 
 exit_status=0