vim-patch:8.0.1510: cannot assert beep #9938

Problem:    Cannot test if a command causes a beep.
Solution:   Add assert_beeps().
b48e96f61c

src/nvim/eval.c

@@ -6877,6 +6877,27 @@ static void assert_equal_common(typval_T *argvars, assert_type_T atype)
   }
 }
 
+static void f_assert_beeps(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  const char *const cmd = tv_get_string_chk(&argvars[0]);
+  garray_T ga;
+
+  called_vim_beep = false;
+  suppress_errthrow = true;
+  emsg_silent = false;
+  do_cmdline_cmd(cmd);
+  if (!called_vim_beep) {
+    prepare_assert_error(&ga);
+    ga_concat(&ga, (const char_u *)"command did not beep: ");
+    ga_concat(&ga, (const char_u *)cmd);
+    assert_error(&ga);
+    ga_clear(&ga);
+  }
+
+  suppress_errthrow = false;
+  emsg_on_display = false;
+}
+
 // "assert_equal(expected, actual[, msg])" function
 static void f_assert_equal(typval_T *argvars, typval_T *rettv, FunPtr fptr)
 {

src/nvim/eval.lua

@@ -25,6 +25,7 @@ return {
     arglistid={args={0, 2}},
     argv={args={0, 1}},
     asin={args=1, func="float_op_wrapper", data="&asin"},  -- WJMc
+    assert_beeps={args={1, 2}},
     assert_equal={args={2, 3}},
     assert_exception={args={1, 2}},
     assert_fails={args={1, 2}},

src/nvim/globals.h

@@ -227,6 +227,7 @@ EXTERN dict_T vimvardict;                   /* Dictionary with v: variables */
 EXTERN dict_T globvardict;                  /* Dictionary with g: variables */
 EXTERN int did_emsg;                        /* set by emsg() when the message
                                                is displayed or thrown */
+EXTERN bool called_vim_beep;                // set if vim_beep() is called
 EXTERN int did_emsg_syntax;                 /* did_emsg set because of a
                                                syntax error */
 EXTERN int called_emsg;                     /* always set by emsg() */

src/nvim/misc1.c

@@ -2578,6 +2578,8 @@ void beep_flush(void)
 // val is one of the BO_ values, e.g., BO_OPER
 void vim_beep(unsigned val)
 {
+  called_vim_beep = true;
+
   if (emsg_silent == 0) {
     if (!((bo_flags & val) || (bo_flags & BO_ALL))) {
       if (p_vb) {
@@ -2587,8 +2589,9 @@ void vim_beep(unsigned val)
       }
     }
 
-    /* When 'verbose' is set and we are sourcing a script or executing a
-     * function give the user a hint where the beep comes from. */
+    // When 'debug' contains "beep" produce a message.  If we are sourcing
+    // a script or executing a function give the user a hint where the beep
+    // comes from.
     if (vim_strchr(p_debug, 'e') != NULL) {
       msg_source(HL_ATTR(HLF_W));
       msg_attr(_("Beep!"), HL_ATTR(HLF_W));

src/nvim/testdir/test_normal.vim

@@ -2272,6 +2272,8 @@ endfunc
 
 func! Test_normal45_drop()
   if !has('dnd')
+    " The ~ register does not exist
+    call assert_beeps('norm! "~')
     return
   endif