Fixed unit test

_concepts.txt

@@ -1,10 +1,41 @@
 def concept one as 1
 def concept two as 2
 def concept three as 3
-def concept one as 1
-
-def concept two as 2
-
-def concept three as 3
-
 def concept four as 4
+def concept five as 5
+def concept six as 6
+def concept seven as 7
+def concept eight as 8
+def concept nine as 9
+def concept ten as 10
+def concept eleven as 11
+def concept twelve as 12
+def concept thirteen as 13
+def concept fourteen as 14
+def concept fifteen as 15
+def concept sixteen as 16
+def concept seventeen as 17
+def concept eighteen as 18
+def concept nineteen as 19
+def concept twenty as 20
+def concept numbers
+def one isa number
+def two isa number
+def three isa number
+def four isa number
+def five isa number
+def six isa number
+def seven isa number
+def eight isa number
+def nine isa number
+def ten isa number
+def eleven isa number
+def twelve isa number
+def thirteen isa number
+def fourteen isa number
+def fifteen isa number
+def sixteen isa number
+def seventeen isa number
+def eighteen isa number
+def nineteen isa number
+def twenty isa number