test(runner): fix test runner check for errorContains

Author: daprahamian

test/functional/runner/index.js

@@ -585,7 +585,7 @@ function testOperation(operation, obj, context, options) {
     const result = operation.result;
 
     if (
-      result.errorContains ||
+      result.errorContains != null ||
       result.errorCodeName ||
       result.errorLabelsContain ||
       result.errorLabelsOmit