NIFI-10622 Fix Flaky Test

[Kerr0220]

Summary

NIFI-10622

Following the problem in the issue NIFI-10622, I looked through the test code and find that the checksum calculated by test peer is hard coded as "3057746557" in testTransferTwoFiles():

// Commit transaction        
final int flowFileSent = serverProtocol.commitTransferTransaction(peer, "3058746557"); 

Therefore, the problem must be caused by the other peer, where the checksum is calculated as another value.

Then, I dived into the codes where the checksum is calculated and found that this non-deterministic problem is caused by

// module: nifi-nar-bundles/nifi-framework-bundle/nifi-framework/nifi-site-to-site
// file: remote/protocol/AbstractFlowFileServerProtocol.java
final DataPacket dataPacket = new StandardDataPacket(toSend.getAttributes(), in, toSend.getSize());

since the determination of getAttributed() is:

public Map<String, String> getAttributes() {
    return Collections.unmodifiableMap(this.attributes);
}

and the order of elements return by it is non-deterministic.

To minimize the influence, I sort the elements after retrieving them and store them in LinkedHashMap:

LinkedHashMap<String, String> attributes = new LinkedHashMap<>();
String[] keySet = toSend.getAttributes().keySet().toArray(new String[0]);
Arrays.sort(keySet);
for(String key: keySet){
    attributes.put(key, toSend.getAttributes().get(key));
}
final DataPacket dataPacket = new StandardDataPacket(attributes, in, toSend.getSize());

In this case, the checksum will always be calculated as 4171232842. So I changed the checksum in the test case to this value.

Finally, this test is not flaky and can pass NonDex's check.

Tracking

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