diff --git a/core/system/system-tests.factor b/core/system/system-tests.factor
index 14e34ccb17..d5a48080c2 100755
--- a/core/system/system-tests.factor
+++ b/core/system/system-tests.factor
@@ -12,3 +12,10 @@ os unix? [
     [ ] [ "envs" get set-os-envs ] unit-test
     [ t ] [ os-envs "envs" get = ] unit-test
 ] when
+
+[ ] [ "factor-test-key-1" unset-os-env ] unit-test
+[ ] [ "ps3" "factor-test-key-1" set-os-env ] unit-test
+[ "ps3" ] [ "factor-test-key-1" os-env ] unit-test
+[ ] [ "factor-test-key-1" unset-os-env ] unit-test
+[ f ] [ "factor-test-key-1" os-env ] unit-test
+