diff --git a/test/runner-unix.c b/test/runner-unix.c
index d0ebfbf0..668dc95e 100644
--- a/test/runner-unix.c
+++ b/test/runner-unix.c
@@ -40,6 +40,11 @@
 
 /* Do platform-specific initialization. */
 void platform_init(int argc, char **argv) {
+  /* Running the tests as root is not smart - don't do it. */
+  if (getuid() == 0) {
+    fprintf(stderr, "Running the tests as root is not safe.\n");
+    exit(1);
+  }
   /* Disable stdio output buffering. */
   setvbuf(stdout, NULL, _IONBF, 0);
   setvbuf(stderr, NULL, _IONBF, 0);