provided code

src/tests/userprog/wait-bad-pid.c

@@ -0,0 +1,14 @@
+/* Waits for an invalid pid.  This may fail, returning -1 from wait, 
+   or terminate the process with -1 exit code.                    */
+
+#include <syscall.h>
+#include "tests/lib.h"
+#include "tests/main.h"
+
+void
+test_main (void) 
+{
+  int retval = wait ((pid_t) 0x0c020301);
+  if (retval != -1)
+    fail ("process should have called exit(-1) or invalid wait syscall should have returned -1");
+}