Main Compliance testing for simple UNARY ops

For RECIPROCAL, RSQRT, CEIL, FLOOR, ABS, NEGATE & IDENTITY.
Improved ULP informational output.

Signed-off-by: Jeremy Johnson <jeremy.johnson@arm.com>
Change-Id: I49644573b4c9a30b2b9d6c9624f2a1d46976a378
diff --git a/verif/generator/tosa_error_if.py b/verif/generator/tosa_error_if.py
index ed1a941..86be347 100644
--- a/verif/generator/tosa_error_if.py
+++ b/verif/generator/tosa_error_if.py
@@ -343,6 +343,9 @@
         Returns:
             True if the result matches the expected result; otherwise False
         """
+        if validator_fcns is None:
+            # Nothing to do
+            return True
         overall_result = True
         for val_fcn in validator_fcns:
             val_result = val_fcn(True, **kwargs)