diff -r 755d165633ec -r 1f8005b4cdf6 marking2/docdiff_test2.scala
--- a/marking2/docdiff_test2.scala	Tue Nov 19 06:38:20 2019 +0000
+++ b/marking2/docdiff_test2.scala	Fri Nov 22 16:41:45 2019 +0000
@@ -4,3 +4,7 @@
 assert(occurrences(List("a", "b", "b", "c", "d")) == Map("a" -> 1, "b" -> 2, "c" -> 1, "d" -> 1))
 
 assert(occurrences(List("d", "b", "d", "b", "d")) == Map("d" -> 3, "b" -> 2))
+
+assert(occurrences(List("b", "b", "b", "b", "b")) == Map("b" -> 5))
+
+assert(occurrences(Nil) == Map())