patch 8.0.1374: CTRL-A does not work with an empty line

Problem:    CTRL-A does not work with an empty line. (Alex)
Solution:   Decrement the end only once. (Hirohito Higashi, closes #2387)
diff --git a/src/testdir/test_increment.vim b/src/testdir/test_increment.vim
index 8bfd95d..ad355dc 100644
--- a/src/testdir/test_increment.vim
+++ b/src/testdir/test_increment.vim
@@ -364,11 +364,25 @@
 "     Expected:
 "     1) Ctrl-a on visually selected zero
 "     111
+"
+" Also: 019 with "01" selected increments to "029".
 func Test_visual_increment_15()
   call setline(1, ["101"])
   exec "norm! lv\<C-A>"
   call assert_equal(["111"], getline(1, '$'))
   call assert_equal([0, 1, 2, 0], getpos('.'))
+
+  call setline(1, ["019"])
+  exec "norm! 0vl\<C-A>"
+  call assert_equal("029", getline(1))
+
+  call setline(1, ["01239"])
+  exec "norm! 0vlll\<C-A>"
+  call assert_equal("01249", getline(1))
+
+  call setline(1, ["01299"])
+  exec "norm! 0vlll\<C-A>"
+  call assert_equal("1309", getline(1))
 endfunc
 
 " 16) increment right aligned numbers
@@ -756,5 +770,12 @@
   call assert_equal([0, 3, 25, 0], getpos('.'))
 endfunc
 
+func Test_increment_empty_line()
+  new
+  call setline(1, ['0', '0', '0', '0', '0', '0', ''])
+  exe "normal Gvgg\<C-A>"
+  call assert_equal(['1', '1', '1', '1', '1', '1', ''], getline(1, 7))
+  bwipe!
+endfunc
 
 " vim: shiftwidth=2 sts=2 expandtab