The tests MaxNodesPer(Read, Write, HistoryReadData...) are executed also if the value is 0. In the OPC Foundation Profile Description, it says in the Test Case Ids 8 and above:
" Run this test if MaxNodesPerRead exists and is not 0", namely to run the test only if this value is not 0 or it exists.
https://profiles.opcfoundation.org/v104/Reporting/testcases/Server/BaseInfoServerCapabilities.html

In the testing tool, when the value is 0, it is set to the max. available value:

var realValue = itemMaxLen.Value.Value.toUInt32();
if( realValue === 0 ) {
addWarning( "MaxNodesPerRead is set to zero. It should be set to a realistic value. OperationLimit will be limited to this value." );
realValue = MAX_ALLOWED_SIZE;
}

Am I misunderstanding something or this is a small bug?