patch 8.2.0174: various commands not completely tested

Problem:    Various commands not completely tested.
Solution:   Add more test cases. (Yegappan Lakshmanan, closes #5551)
diff --git a/src/testdir/test_textformat.vim b/src/testdir/test_textformat.vim
index 2223be9..a49ef5c 100644
--- a/src/testdir/test_textformat.vim
+++ b/src/testdir/test_textformat.vim
@@ -424,6 +424,14 @@
 	      \ ], getline(1, '$'))
   enew!
 
+  " align text with 'wrapmargin'
+  call setline(1, ['Vim'])
+  set textwidth=0
+  set wrapmargin=60
+  right
+  call assert_equal("\t\t Vim", getline(1))
+  set wrapmargin&
+
   set tw&
 endfunc