Flaky tests in core/graph

[omkrpt]

Describe the bug
Found some flaky tests, along the lines of #3037

Using the latest commit ac60289, the following tests are identified as flaky:

Test 1 : uk.gov.gchq.gaffer.graph.GraphTest#shouldConstructGraphAndCreateViewWithGroups
Test 2 : uk.gov.gchq.gaffer.graph.GraphSerialisableTest#shouldConsumeGraph

To Reproduce

I used a tool called nondex.

Test 1:

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

Failure:

[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)
...

Test 2:

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

Failure:

[ERROR] Tests run: 1, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.586 s <<< FAILURE! -- in uk.gov.gchq.gaffer.graph.GraphSerialisableTest
[ERROR] uk.gov.gchq.gaffer.graph.GraphSerialisableTest.shouldConsumeGraph -- Time elapsed: 0.577 s <<< FAILURE!
org.opentest4j.AssertionFailedError: 

expected: 
  GraphSerialisable[config=GraphConfig[graphId=testGraphId,view=View[{
    "entities" : {
      "e1" : { }
    }
  }],library=uk.gov.gchq.gaffer.store.library.NoGraphLibrary@661d88a,hooks=[uk.gov.gchq.gaffer.graph.hook.NamedViewResolver@4b0b64cc, uk.gov.gchq.gaffer.graph.hook.FunctionAuthoriser@59ce792e]],schema=Schema[{
    "entities" : {
      "e1" : {
        "vertex" : "string"
      }
    },
    "types" : {
      "string" : {
        "class" : "java.lang.String"
      }
    }
  }],properties={gaffer.store.class=uk.gov.gchq.gaffer.integration.store.TestStore, gaffer.store.properties.class=uk.gov.gchq.gaffer.store.StoreProperties}]
 but was: 
  GraphSerialisable[config=GraphConfig[graphId=testGraphId,view=View[{
    "entities" : {
      "e1" : { }
    }
  }],library=uk.gov.gchq.gaffer.store.library.NoGraphLibrary@56399b9e,hooks=[uk.gov.gchq.gaffer.graph.hook.NamedViewResolver@34b9eb03, uk.gov.gchq.gaffer.graph.hook.FunctionAuthoriser@43fda8d9]],schema=Schema[{
    "entities" : {
      "e1" : {
        "vertex" : "string"
      }
    },
    "types" : {
      "string" : {
        "class" : "java.lang.String"
      }
    }
  }],properties={gaffer.store.properties.class=uk.gov.gchq.gaffer.store.StoreProperties, gaffer.store.class=uk.gov.gchq.gaffer.integration.store.TestStore}]
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
	at java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
	at java.base/jdk.internal.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
	at uk.gov.gchq.gaffer.graph.GraphSerialisableTest.shouldConsumeGraph(GraphSerialisableTest.java:98)
...

The problem
In both of the tests, the objects to be compared contain elements that are arranged in a non-deterministic order.

[omkrpt]

Have updated the PRs to fix these flaky tests (#3155, #3156) and marked them ready for review @tb06904 @t92549. Not sure why this issue was marked completed. I hope this is useful. Happy to help anyway.