BibConvert: re-fix formatting option WORDS

* Amends previous fix to formatting option which caused
  some tests to fail.

* Adds regression test.

modules/bibconvert/lib/bibconvert.py

@@ -1005,17 +1005,19 @@ def FormatField(value, fn):
             out = value
 
     elif (fn == "WORDS"):
-        wordlist = [value]
         par = set_par_defaults(par, ",")
-        max_num_words = int(par[0])
-        if (par[1] == "R"):
-            words = value.split(" ")
-            wordlist = words[:max_num_words]
+        words = value.split(" ")
+        try:
+            max_num_words = int(par[0])
+        except ValueError:
+            max_num_words = len(words)
+
         if (par[1] == "L"):
-            words = value.split(" ")
             words.reverse()
             wordlist = words[:max_num_words]
             wordlist.reverse()
+        else:
+            wordlist = words[:max_num_words]
         out = " ".join(wordlist)
 
     elif (fn == "MINL"):

modules/bibconvert/lib/bibconvert_tests.py

@@ -203,6 +203,12 @@ def test_words_right(self):
         self.assertEqual("Sep",
                          bibconvert.FormatField(test_input, "WORDS(1,R)"))
 
+    def test_words_exceed_wordcount(self):
+        """bibconvert - WORDS(2,R) when less then 2 words in value"""
+        test_input = "ab"
+        self.assertEqual(test_input,
+                         bibconvert.FormatField(test_input, "WORDS(2,R)"))
+
 class TestBCCL(unittest.TestCase):
     """Test bibconvert BCCL compliance"""