diff --git a/util/test/rdtest/util.py b/util/test/rdtest/util.py
index 2a42d1ca8..368eb5dfa 100644
--- a/util/test/rdtest/util.py
+++ b/util/test/rdtest/util.py
@@ -246,7 +246,7 @@ def value_compare(ref, data):
             return False
 
         # Special handling for NaNs
-        if math.isnan(ref) == math.isnan(data):
+        if math.isnan(ref) and math.isnan(data):
             return True
 
         # Floats are equal if the absolute difference is less than epsilon times the largest.