diff --git a/src/eval.c b/src/eval.c
index ce83143..a653b89 100644
--- a/src/eval.c
+++ b/src/eval.c
@@ -583,7 +583,6 @@
 static void f_foreground(typval_T *argvars, typval_T *rettv);
 static void f_function(typval_T *argvars, typval_T *rettv);
 static void f_garbagecollect(typval_T *argvars, typval_T *rettv);
-static void f_garbagecollect_for_testing(typval_T *argvars, typval_T *rettv);
 static void f_get(typval_T *argvars, typval_T *rettv);
 static void f_getbufline(typval_T *argvars, typval_T *rettv);
 static void f_getbufvar(typval_T *argvars, typval_T *rettv);
@@ -806,7 +805,17 @@
 static void f_taglist(typval_T *argvars, typval_T *rettv);
 static void f_tagfiles(typval_T *argvars, typval_T *rettv);
 static void f_tempname(typval_T *argvars, typval_T *rettv);
-static void f_test(typval_T *argvars, typval_T *rettv);
+static void f_test_garbagecollect_now(typval_T *argvars, typval_T *rettv);
+#ifdef FEAT_JOB_CHANNEL
+static void f_test_null_channel(typval_T *argvars, typval_T *rettv);
+#endif
+static void f_test_null_dict(typval_T *argvars, typval_T *rettv);
+#ifdef FEAT_JOB_CHANNEL
+static void f_test_null_job(typval_T *argvars, typval_T *rettv);
+#endif
+static void f_test_null_list(typval_T *argvars, typval_T *rettv);
+static void f_test_null_partial(typval_T *argvars, typval_T *rettv);
+static void f_test_null_string(typval_T *argvars, typval_T *rettv);
 #ifdef FEAT_FLOAT
 static void f_tan(typval_T *argvars, typval_T *rettv);
 static void f_tanh(typval_T *argvars, typval_T *rettv);
@@ -6925,7 +6934,7 @@
 
 /*
  * Do garbage collection for lists and dicts.
- * When "testing" is TRUE this is called from garbagecollect_for_testing().
+ * When "testing" is TRUE this is called from test_garbagecollect_now().
  * Return TRUE if some memory was freed.
  */
     int
@@ -8451,7 +8460,6 @@
     {"foreground",	0, 0, f_foreground},
     {"function",	1, 3, f_function},
     {"garbagecollect",	0, 1, f_garbagecollect},
-    {"garbagecollect_for_testing",	0, 0, f_garbagecollect_for_testing},
     {"get",		2, 3, f_get},
     {"getbufline",	2, 3, f_getbufline},
     {"getbufvar",	2, 3, f_getbufvar},
@@ -8681,7 +8689,17 @@
     {"tanh",		1, 1, f_tanh},
 #endif
     {"tempname",	0, 0, f_tempname},
-    {"test",		1, 1, f_test},
+    {"test_garbagecollect_now",	0, 0, f_test_garbagecollect_now},
+#ifdef FEAT_JOB_CHANNEL
+    {"test_null_channel", 0, 0, f_test_null_channel},
+#endif
+    {"test_null_dict", 0, 0, f_test_null_dict},
+#ifdef FEAT_JOB_CHANNEL
+    {"test_null_job", 0, 0, f_test_null_job},
+#endif
+    {"test_null_list", 0, 0, f_test_null_list},
+    {"test_null_partial", 0, 0, f_test_null_partial},
+    {"test_null_string", 0, 0, f_test_null_string},
 #ifdef FEAT_TIMERS
     {"timer_start",	2, 3, f_timer_start},
     {"timer_stop",	1, 1, f_timer_stop},
@@ -12374,17 +12392,6 @@
 }
 
 /*
- * "garbagecollect_for_testing()" function
- */
-    static void
-f_garbagecollect_for_testing(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
-{
-    /* This is dangerous, any Lists and Dicts used internally may be freed
-     * while still in use. */
-    garbage_collect(TRUE);
-}
-
-/*
  * "get()" function
  */
     static void
@@ -20602,35 +20609,6 @@
     } while (x == 'I' || x == 'O');
 }
 
-/*
- * "test(list)" function: Just checking the walls...
- */
-    static void
-f_test(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
-{
-    /* Used for unit testing.  Change the code below to your liking. */
-#if 0
-    listitem_T	*li;
-    list_T	*l;
-    char_u	*bad, *good;
-
-    if (argvars[0].v_type != VAR_LIST)
-	return;
-    l = argvars[0].vval.v_list;
-    if (l == NULL)
-	return;
-    li = l->lv_first;
-    if (li == NULL)
-	return;
-    bad = get_tv_string(&li->li_tv);
-    li = li->li_next;
-    if (li == NULL)
-	return;
-    good = get_tv_string(&li->li_tv);
-    rettv->vval.v_number = test_edit_score(bad, good);
-#endif
-}
-
 #ifdef FEAT_FLOAT
 /*
  * "tan()" function
@@ -20663,6 +20641,63 @@
 }
 #endif
 
+/*
+ * "test_garbagecollect_now()" function
+ */
+    static void
+f_test_garbagecollect_now(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
+{
+    /* This is dangerous, any Lists and Dicts used internally may be freed
+     * while still in use. */
+    garbage_collect(TRUE);
+}
+
+#ifdef FEAT_JOB_CHANNEL
+    static void
+f_test_null_channel(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
+{
+    rettv->v_type = VAR_CHANNEL;
+    rettv->vval.v_channel = NULL;
+}
+#endif
+
+    static void
+f_test_null_dict(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
+{
+    rettv->v_type = VAR_DICT;
+    rettv->vval.v_dict = NULL;
+}
+
+#ifdef FEAT_JOB_CHANNEL
+    static void
+f_test_null_job(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
+{
+    rettv->v_type = VAR_JOB;
+    rettv->vval.v_job = NULL;
+}
+#endif
+
+    static void
+f_test_null_list(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
+{
+    rettv->v_type = VAR_LIST;
+    rettv->vval.v_list = NULL;
+}
+
+    static void
+f_test_null_partial(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
+{
+    rettv->v_type = VAR_PARTIAL;
+    rettv->vval.v_partial = NULL;
+}
+
+    static void
+f_test_null_string(typval_T *argvars UNUSED, typval_T *rettv UNUSED)
+{
+    rettv->v_type = VAR_STRING;
+    rettv->vval.v_string = NULL;
+}
+
 #if defined(FEAT_JOB_CHANNEL) || defined(FEAT_TIMERS) || defined(PROTO)
 /*
  * Get a callback from "arg".  It can be a Funcref or a function name.