make tests green again

tests/rational/trat_init.nim

@@ -1,10 +1,14 @@
 discard """
-  file: "trat_init.nim"
-  exitcode: "1"
+  output: '''true'''
 """
 import rationals
 var
   z = Rational[int](num: 0, den: 1)
   o = initRational(num=1, den=1)
   a = initRational(1, 2)
-  r = initRational(1, 0)  # this fails - no zero denominator
+
+try:
+  var
+    r = initRational(1, 0)  # this fails - no zero denominator
+except AssertionError:
+  echo "true"