tracks/haskell/exercises/isbn-verifier/test/Tests.hs in trackler-2.2.1.85 vs tracks/haskell/exercises/isbn-verifier/test/Tests.hs in trackler-2.2.1.86

@@ -69,6 +69,10 @@
                }
         , Case { description = "check digit of X should not be used for 0"
                , input       = "3-598-21515-X"
                , expected    = False
                }
+        , Case { description = "empty isbn"
+               , input       = ""
+               , expected    = False
+               }
         ]