patch 8.0.1209: still too many old style tests

Problem:    Still too many old style tests.
Solution:   Convert a few more tests to new style. (Yegappan Lakshmanan,
            closes #2230)
diff --git a/src/testdir/test_join.vim b/src/testdir/test_join.vim
index 8a028f1..1c97414 100644
--- a/src/testdir/test_join.vim
+++ b/src/testdir/test_join.vim
@@ -11,3 +11,25 @@
   call assert_equal('one two three four', getline(1))
   quit!
 endfunc
+
+" Tests for setting the '[,'] marks when joining lines.
+func Test_join_marks()
+  enew
+  call append(0, [
+	      \ "\t\tO sodales, ludite, vos qui",
+	      \ "attamen consulite per voster honur. Tua pulchra " .
+	      \ "facies me fay planszer milies",
+	      \ "",
+	      \ "This line.",
+	      \ "Should be joined with the next line",
+	      \ "and with this line"])
+
+  normal gg0gqj
+  call assert_equal([0, 1, 1, 0], getpos("'["))
+  call assert_equal([0, 2, 1, 0], getpos("']"))
+
+  /^This line/;'}-join
+  call assert_equal([0, 4, 11, 0], getpos("'["))
+  call assert_equal([0, 4, 67, 0], getpos("']"))
+  enew!
+endfunc