diff --git a/src/testdir/test_join.vim b/src/testdir/test_join.vim
index 78835b2..5801c2f 100644
--- a/src/testdir/test_join.vim
+++ b/src/testdir/test_join.vim
@@ -9,6 +9,27 @@
   call setline(1, ['one', 'two', 'three', 'four'])
   normal 10J
   call assert_equal('one two three four', getline(1))
+
+  call setline(1, ['one', '', 'two'])
+  normal J
+  call assert_equal('one', getline(1))
+
+  call setline(1, ['one', ' ', 'two'])
+  normal J
+  call assert_equal('one', getline(1))
+
+  call setline(1, ['one', '', '', 'two'])
+  normal JJ
+  call assert_equal('one', getline(1))
+
+  call setline(1, ['one', ' ', ' ', 'two'])
+  normal JJ
+  call assert_equal('one', getline(1))
+
+  call setline(1, ['one', '', '', 'two'])
+  normal 2J
+  call assert_equal('one', getline(1))
+
   quit!
 endfunc