vim-patch:8.2.0426: some errors were not tested for

Problem:    Some errors were not tested for.
Solution:   Add tests. (Dominique Pelle, closes vim/vim#5824)
9b9be007e7

Cherry-pick get_highest_fnum() from patch 8.1.1908 to make tests pass.

src/nvim/buffer.c

@@ -94,11 +94,19 @@ static char *e_buflocked = N_("E937: Attempt to delete a buffer that is in use")
 // Number of times free_buffer() was called.
 static int buf_free_count = 0;
 
+static int top_file_num = 1;            ///< highest file number
+
 typedef enum {
   kBffClearWinInfo = 1,
   kBffInitChangedtick = 2,
 } BufFreeFlags;
 
+/// @return  the highest possible buffer number
+int get_highest_fnum(void)
+{
+  return top_file_num - 1;
+}
+
 /// Read data from buffer for retrying.
 ///
 /// @param read_stdin  read file from stdin, otherwise fifo
@@ -1644,8 +1652,6 @@ void no_write_message_nobang(const buf_T *const buf)
 // functions for dealing with the buffer list
 //
 
-static int top_file_num = 1;            ///< highest file number
-
 /// Initialize b:changedtick and changedtick_val attribute
 ///
 /// @param[out]  buf  Buffer to initialize for.

src/nvim/ex_docmd.c

@@ -4616,8 +4616,9 @@ char *invalid_range(exarg_T *eap)
       }
       break;
     case ADDR_BUFFERS:
-      if (eap->line1 < firstbuf->b_fnum
+      // Only a boundary check, not whether the buffers actually
-          || eap->line2 > lastbuf->b_fnum) {
+      // exist.
+      if (eap->line1 < 1 || eap->line2 > get_highest_fnum()) {
         return _(e_invrange);
       }
       break;

src/nvim/testdir/test_buffer.vim

@@ -146,6 +146,7 @@ endfunc
 func Test_bdelete_cmd()
   %bwipe!
   call assert_fails('bdelete 5', 'E516:')
+  call assert_fails('1,1bdelete 1 2', 'E488:')
 
   " Deleting a unlisted and unloaded buffer
   edit Xfile1

src/nvim/testdir/test_options.vim

@@ -290,9 +290,10 @@ func Test_set_errors()
   call assert_fails('set regexpengine=3', 'E474:')
   call assert_fails('set history=10001', 'E474:')
   call assert_fails('set numberwidth=21', 'E474:')
-  call assert_fails('set colorcolumn=-a')
+  call assert_fails('set colorcolumn=-a', 'E474:')
-  call assert_fails('set colorcolumn=a')
+  call assert_fails('set colorcolumn=a', 'E474:')
-  call assert_fails('set colorcolumn=1,')
+  call assert_fails('set colorcolumn=1,', 'E474:')
+  call assert_fails('set colorcolumn=1;', 'E474:')
   call assert_fails('set cmdheight=-1', 'E487:')
   call assert_fails('set cmdwinheight=-1', 'E487:')
   if has('conceal')
@@ -343,9 +344,13 @@ func Test_set_errors()
     call assert_fails('set guicursor=i-ci,r-cr:h', 'E545:')
     call assert_fails('set guicursor=i-ci', 'E545:')
     call assert_fails('set guicursor=x', 'E545:')
+    call assert_fails('set guicursor=x:', 'E546:')
     call assert_fails('set guicursor=r-cr:horx', 'E548:')
     call assert_fails('set guicursor=r-cr:hor0', 'E549:')
   endif
+  if has('mouseshape')
+    call assert_fails('se mouseshape=i-r:x', 'E547:')
+  endif
   call assert_fails('set backupext=~ patchmode=~', 'E589:')
   call assert_fails('set winminheight=10 winheight=9', 'E591:')
   call assert_fails('set winminwidth=10 winwidth=9', 'E592:')

src/nvim/testdir/test_window_cmd.vim

@@ -172,6 +172,35 @@ func Test_window_split_edit_bufnr()
   %bw!
 endfunc
 
+func Test_window_split_no_room()
+  " N horizontal windows need >= 2*N + 1 lines:
+  " - 1 line + 1 status line in each window
+  " - 1 Ex command line
+  "
+  " 2*N + 1 <= &lines
+  " N <= (lines - 1)/2
+  "
+  " Beyond that number of windows, E36: Not enough room is expected.
+  let hor_win_count = (&lines - 1)/2
+  let hor_split_count = hor_win_count - 1
+  for s in range(1, hor_split_count) | split | endfor
+  call assert_fails('split', 'E36:')
+
+  " N vertical windows need >= 2*(N - 1) + 1 columns:
+  " - 1 column + 1 separator for each window (except last window)
+  " - 1 column for the last window which does not have separator
+  "
+  " 2*(N - 1) + 1 <= &columns
+  " 2*N - 1 <= &columns
+  " N <= (&columns + 1)/2
+  let ver_win_count = (&columns + 1)/2
+  let ver_split_count = ver_win_count - 1
+  for s in range(1, ver_split_count) | vsplit | endfor
+  call assert_fails('vsplit', 'E36:')
+
+  %bw!
+endfunc
+
 func Test_window_exchange()
   e Xa