Test: Added space separator for DOM output

- When using multiple arguments (task _get 1.due 2.due), the results are
  separated by a space, even if the values are blank. The consistency of this
  is good, but the test ignored it.

test/sequence.t

@@ -62,7 +62,7 @@ class TestSequences(TestCase):
 
         self.t("1,2 stop")
         code, out, err = self.t("_get 1.start 2.start")
-        self.assertEqual("\n", out)
+        self.assertEqual(" \n", out)  # Space separating the two blank values.
 
     def test_sequence_modify(self):
         """Test sequences in modify"""