vim-patch:8.2.4052: not easy to resize a window from a plugin (#17028)

src/nvim/testdir/test_window_cmd.vim

@@ -939,4 +939,104 @@ func Test_window_resize()
   %bwipe!
 endfunc
 
+func Test_win_move_separator()
+  edit a
+  leftabove vsplit b
+  let w = winwidth(0)
+  " check win_move_separator from left window on left window
+  call assert_equal(1, winnr())
+  for offset in range(5)
+    call assert_true(win_move_separator(0, offset))
+    call assert_equal(w + offset, winwidth(0))
+    call assert_true(0->win_move_separator(-offset))
+    call assert_equal(w, winwidth(0))
+  endfor
+  " check win_move_separator from right window on left window number
+  wincmd l
+  call assert_notequal(1, winnr())
+  for offset in range(5)
+    call assert_true(1->win_move_separator(offset))
+    call assert_equal(w + offset, winwidth(1))
+    call assert_true(win_move_separator(1, -offset))
+    call assert_equal(w, winwidth(1))
+  endfor
+  " check win_move_separator from right window on left window ID
+  let id = win_getid(1)
+  for offset in range(5)
+    call assert_true(win_move_separator(id, offset))
+    call assert_equal(w + offset, winwidth(id))
+    call assert_true(id->win_move_separator(-offset))
+    call assert_equal(w, winwidth(id))
+  endfor
+  " check that win_move_separator doesn't error with offsets beyond moving
+  " possibility
+  call assert_true(win_move_separator(id, 5000))
+  call assert_true(winwidth(id) > w)
+  call assert_true(win_move_separator(id, -5000))
+  call assert_true(winwidth(id) < w)
+  " check that win_move_separator returns false for an invalid window
+  wincmd =
+  let w = winwidth(0)
+  call assert_false(win_move_separator(-1, 1))
+  call assert_equal(w, winwidth(0))
+  " check that win_move_separator returns false for a floating window
+  let id = nvim_open_win(
+        \ 0, 0, #{relative: 'editor', row: 2, col: 2, width: 5, height: 3})
+  let w = winwidth(id)
+  call assert_false(win_move_separator(id, 1))
+  call assert_equal(w, winwidth(id))
+  call nvim_win_close(id, 1)
+  %bwipe!
+endfunc
+
+func Test_win_move_statusline()
+  edit a
+  leftabove split b
+  let h = winheight(0)
+  " check win_move_statusline from top window on top window
+  call assert_equal(1, winnr())
+  for offset in range(5)
+    call assert_true(win_move_statusline(0, offset))
+    call assert_equal(h + offset, winheight(0))
+    call assert_true(0->win_move_statusline(-offset))
+    call assert_equal(h, winheight(0))
+  endfor
+  " check win_move_statusline from bottom window on top window number
+  wincmd j
+  call assert_notequal(1, winnr())
+  for offset in range(5)
+    call assert_true(1->win_move_statusline(offset))
+    call assert_equal(h + offset, winheight(1))
+    call assert_true(win_move_statusline(1, -offset))
+    call assert_equal(h, winheight(1))
+  endfor
+  " check win_move_statusline from bottom window on top window ID
+  let id = win_getid(1)
+  for offset in range(5)
+    call assert_true(win_move_statusline(id, offset))
+    call assert_equal(h + offset, winheight(id))
+    call assert_true(id->win_move_statusline(-offset))
+    call assert_equal(h, winheight(id))
+  endfor
+  " check that win_move_statusline doesn't error with offsets beyond moving
+  " possibility
+  call assert_true(win_move_statusline(id, 5000))
+  call assert_true(winheight(id) > h)
+  call assert_true(win_move_statusline(id, -5000))
+  call assert_true(winheight(id) < h)
+  " check that win_move_statusline returns false for an invalid window
+  wincmd =
+  let h = winheight(0)
+  call assert_false(win_move_statusline(-1, 1))
+  call assert_equal(h, winheight(0))
+  " check that win_move_statusline returns false for a floating window
+  let id = nvim_open_win(
+        \ 0, 0, #{relative: 'editor', row: 2, col: 2, width: 5, height: 3})
+  let h = winheight(id)
+  call assert_false(win_move_statusline(id, 1))
+  call assert_equal(h, winheight(id))
+  call nvim_win_close(id, 1)
+  %bwipe!
+endfunc
+
 " vim: shiftwidth=2 sts=2 expandtab