fixing flaky test shouldConstructGraphAndCreateViewWithGroups

[omkrpt]

What is the purpose of this PR

• Linked issue
• This PR fixes the flaky test: uk.gov.gchq.gaffer.graph.GraphTest#shouldConstructGraphAndCreateViewWithGroups
• The test may fail or pass without changes made to the source code when it is run in different JVMs due to the non-deterministic ordering when sets are converted to arrays.

Why the test fails

• The assertions at L925-L926 in this test compare the keys of Map objects with the keySet of Maps in resultView.
• However, while invoking the java.util.Map.keySet() is necessary for comparison, the second conversion by calling java.util.Set.toArray() returns the elements in a non-deterministic order.

How to reproduce the test failure

I used a tool called nondex.

mvn install -pl core/graph -am -DskipTests
mvn -pl core/graph test -Dtest=uk.gov.gchq.gaffer.graph.GraphTest#shouldConstructGraphAndCreateViewWithGroups
mvn -pl core/graph edu.illinois:nondex-maven-plugin:2.1.1:nondex -Dtest=uk.gov.gchq.gaffer.graph.GraphTest#shouldConstructGraphAndCreateViewWithGroups

Expected results

• The test should run successfully when run with NonDex.

Actual results
We get the following failures:

[ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.551 s <<< FAILURE! -- in uk.gov.gchq.gaffer.graph.GraphTest
[ERROR] uk.gov.gchq.gaffer.graph.GraphTest.shouldConstructGraphAndCreateViewWithGroups(Store) -- Time elapsed: 0.537 s <<< FAILURE!
org.opentest4j.AssertionFailedError: array contents differ at index [0], expected: <entity2> but was: <entity3>
	at org.junit.jupiter.api.AssertionFailureBuilder.build(AssertionFailureBuilder.java:151)
	at org.junit.jupiter.api.AssertionFailureBuilder.buildAndThrow(AssertionFailureBuilder.java:132)
	at org.junit.jupiter.api.AssertArrayEquals.failArraysNotEqual(AssertArrayEquals.java:440)
	at org.junit.jupiter.api.AssertArrayEquals.assertArrayElementsEqual(AssertArrayEquals.java:389)
	at org.junit.jupiter.api.AssertArrayEquals.assertArrayEquals(AssertArrayEquals.java:346)
	at org.junit.jupiter.api.AssertArrayEquals.assertArrayEquals(AssertArrayEquals.java:159)
	at org.junit.jupiter.api.AssertArrayEquals.assertArrayEquals(AssertArrayEquals.java:155)
	at org.junit.jupiter.api.Assertions.assertArrayEquals(Assertions.java:1453)
	at uk.gov.gchq.gaffer.graph.GraphTest.shouldConstructGraphAndCreateViewWithGroups(GraphTest.java:925)
...

Description of fix
Comparing the sets directly, without converting them to arrays.

Maven logs for before and after the fix:
graphTestFail.txt
graphTestSuccess.txt

Logs for flakiness detected in initial commits:
graphTestFail_15fa8c3bb.txt
graphTestFail_6c4f85096.txt