Fix flaky test in LogMessageTest

[bbelide2]

Change Assert condition to check on both map orders in a flaky test in LogMessageTest to make it non-flaky.

Flaky test

cn.hippo4j.common.toolkit.logtracing.LogMessageTest.testToStringShouldPrintMessageAndAllKeyAndValuePairs

https://github.com/bbelide2/hippo4j/blob/fec58a5ecaca0f749abcdf076f13d6f0ba6267b2/infra/common/src/test/java/cn/hippo4j/common/toolkit/logtracing/LogMessageTest.java#L81

Problem

Test testToStringShouldPrintMessageAndAllKeyAndValuePairs in LogMessageTest is detected as flaky with the NonDex tool. The test failed with the following error:

Error:
Failed tests:   testToStringShouldPrintMessageAndAllKeyAndValuePairs(cn.hippo4j.common.toolkit.logtracing.LogMessageTest): expected: <messagekey1=value1||key2=value2> but was: <messagekey2=value2||key1=value1>

Root cause

In this test, 2 key-value pairs are set to the kvs field (ConcurrentHashMap) of logMessage object along with s string message. Then, logMessage.toString() is called and the response is compared with hard-coded strings. logMessage.toString() converts the given map to string form along with some other processing. But, ConcurrentHashMap/HashMap may not maintain the order of elements. Therefore, when NonDex tests are run, the order of elements are shuffled and the output is reversed and incorrect thus making the test flaky.

Key-values are inserted this way:

https://github.com/bbelide2/hippo4j/blob/fec58a5ecaca0f749abcdf076f13d6f0ba6267b2/infra/common/src/test/java/cn/hippo4j/common/toolkit/logtracing/LogMessageTest.java#L83-L84

Output is compared this way:

https://github.com/bbelide2/hippo4j/blob/fec58a5ecaca0f749abcdf076f13d6f0ba6267b2/infra/common/src/test/java/cn/hippo4j/common/toolkit/logtracing/LogMessageTest.java#L85

Fix

Usually, switching from HashMap to LinkedHashMap will make tests non-flaky because LinkedHashMap will preserve order of elements. But, we cannot change a ConcurrentHashMap to LinkedHashMap because LinkedHashMap is not thread-safe like ConcurrentHashMap. Therefore, I updated the assert statement to check the output for both the possible orders of elements.

This fix will not affect the code since the change is only made in tests.

How this has been tested?

Java: openjdk version "11.0.20.1"
Maven: Apache Maven 3.6.3

1. Module build - Successful
   Command used -

mvn install -pl infra/common -am -DskipTests

2. Regular test - Successful
   Command used -

mvn -pl infra/common test -Dtest=cn.hippo4j.common.toolkit.logtracing.LogMessageTest#testToStringShouldPrintMessageAndAllKeyAndValuePairs

3. NonDex test - Failed
   Command used -

mvn -pl infra/common edu.illinois:nondex-maven-plugin:2.1.1:nondex -DnondexRuns=10 -Dtest=cn.hippo4j.common.toolkit.logtracing.LogMessageTest#testToStringShouldPrintMessageAndAllKeyAndValuePairs

NonDex tests passed after the fix.