diff --git a/cmdgen.c b/cmdgen.c
index 47795cfe..e1ff0ec8 100644
--- a/cmdgen.c
+++ b/cmdgen.c
@@ -1160,6 +1160,7 @@ void test(int retval, ...)
         printf("\n");
     }
     ret = cmdgen_main(argc, argv);
+    random_clear();
 
     if (ret != retval) {
 	printf("FAILED retval (exp %d got %d):", retval, ret);
diff --git a/putty.h b/putty.h
index de4d410a..ee8952c2 100644
--- a/putty.h
+++ b/putty.h
@@ -1803,6 +1803,13 @@ extern int random_active;
  * calls random_ref on startup and random_unref on shutdown. */
 void random_ref(void);
 void random_unref(void);
+/* random_clear is equivalent to calling random_unref as many times as
+ * necessary to shut down the global PRNG instance completely. It's
+ * not needed in normal applications, but the command-line PuTTYgen
+ * test finds it useful to clean up after each invocation of the
+ * logical main() no matter whether it needed random numbers or
+ * not. */
+void random_clear(void);
 /* random_setup_special is used by PuTTYgen. It makes an extra-big
  * random number generator. */
 void random_setup_special();
diff --git a/sshrand.c b/sshrand.c
index 994c7cfc..b79fafc0 100644
--- a/sshrand.c
+++ b/sshrand.c
@@ -97,16 +97,22 @@ void random_reseed(ptrlen seed)
     prng_seed_finish(global_prng);
 }
 
-void random_unref(void)
+void random_clear(void)
 {
-    assert(random_active > 0);
-    if (random_active == 1) {
+    if (global_prng) {
         random_save_seed();
         expire_timer_context(&random_timer_ctx);
         prng_free(global_prng);
         global_prng = NULL;
+        random_active = 0;
     }
-    random_active--;
+}
+
+void random_unref(void)
+{
+    assert(random_active > 0);
+    if (--random_active == 0)
+        random_clear();
 }
 
 void random_read(void *buf, size_t size)