vim-patch:8.1.0926: no test for :wnext, :wNext and :wprevious

Problem:    No test for :wnext, :wNext and :wprevious.
Solution:   Add a test. (Dominique Pelle, closes vim/vim#3963)
e93e5a504f

src/nvim/testdir/test_alot.vim

@@ -51,3 +51,4 @@ source test_unlet.vim
 source test_utf8.vim
 source test_virtualedit.vim
 source test_window_cmd.vim
+source test_wnext.vim

src/nvim/testdir/test_wnext.vim

@@ -0,0 +1,101 @@
+" Test :wnext :wNext and :wprevious
+
+func Test_wnext()
+  args X1 X2
+
+  call setline(1, '1')
+  wnext
+  call assert_equal(['1'], readfile('X1'))
+  call assert_equal('X2', bufname('%'))
+
+  call setline(1, '2')
+  call assert_fails('wnext', 'E165:')
+  call assert_equal(['2'], readfile('X2'))
+  call assert_equal('X2', bufname('%'))
+
+  " Test :wnext with a single file.
+  args X1
+  call assert_equal('X1', bufname('%'))
+  call assert_fails('wnext', 'E163:')
+
+  " Test :wnext with a count.
+  args X1 X2 X3
+  call assert_equal('X1', bufname('%'))
+  2wnext
+  call assert_equal('X3', bufname('%'))
+
+  " Test :wnext {file}.
+  args X1 X2 X3
+  wnext X4
+  call assert_equal(['1'], readfile('X4'))
+  call assert_equal('X2', bufname('%'))
+  call assert_fails('wnext X4', 'E13:')
+  call assert_equal(['1'], readfile('X4'))
+  wnext! X4
+  call assert_equal(['2'], readfile('X4'))
+  call assert_equal('X3', bufname('%'))
+
+  args X1 X2
+  " Commented out as, E13 occurs on Windows instead of E17
+  "call assert_fails('wnext .', 'E17:')
+  call assert_fails('wnext! .', 'E502:')
+
+  %bwipe!
+  call delete('X1')
+  call delete('X2')
+  call delete('X3')
+  call delete('X4')
+endfunc
+
+func Test_wprevious()
+  args X1 X2
+
+  next
+  call assert_equal('X2', bufname('%'))
+  call setline(1, '2')
+  wprevious
+  call assert_equal(['2'], readfile('X2'))
+  call assert_equal('X1', bufname('%'))
+
+  call setline(1, '1')
+  call assert_fails('wprevious', 'E164:')
+  call assert_fails('wNext', 'E164:')
+
+  " Test :wprevious with a single file.
+  args X1
+  call assert_fails('wprevious', 'E163:')
+  call assert_fails('wNext', 'E163:')
+
+  " Test :wprevious with a count.
+  args X1 X2 X3
+  2next
+  call setline(1, '3')
+  call assert_equal('X3', bufname('%'))
+  2wprevious
+  call assert_equal('X1', bufname('%'))
+  call assert_equal(['3'], readfile('X3'))
+
+  " Test :wprevious {file}
+  args X1 X2 X3
+  2next
+  call assert_equal('X3', bufname('%'))
+  wprevious X4
+  call assert_equal(['3'], readfile('X4'))
+  call assert_equal('X2', bufname('%'))
+  call assert_fails('wprevious X4', 'E13:')
+  call assert_equal(['3'], readfile('X4'))
+  wprevious! X4
+  call assert_equal(['2'], readfile('X4'))
+  call assert_equal('X1', bufname('%'))
+
+  args X1 X2
+  " Commented out as, E13 occurs on Windows instead of E17
+  "call assert_fails('wprevious .', 'E17:')
+  call assert_fails('wprevious! .', 'E502:')
+
+  %bwipe!
+  call delete('X1')
+  call delete('X2')
+  call delete('X3')
+  call delete('X4')
+endfunc