Deflake tests in GraphSONTypedCompatibilityTest, GraphSONUntypedCompatibilityTest and GraphBinaryCompatibilityTest

We observed several tests in GraphSONTypedCompatibilityTest  that exhibited flaky behavior when executed with NonDex. Specifically speaking, we can reproduce them by using the following commands.
```
mvn clean install -DskipTests -Drat.skip=true
```
* Test shouldReadWriteEdge[expect(v2)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWriteEdge[expect(v2)]" -Drat.skip=true
```

* Test shouldReadWriteEdge[expect(v3)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWriteEdge[expect(v3)]" -Drat.skip=true
```

* Test shouldReadWritePath[expect(v2)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWritePath[expect(v2)]" -Drat.skip=true
```

* Test shouldReadWritePath[expect(v3)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWritePath[expect(v3)]" -Drat.skip=true
```

* Test shouldReadWriteProperty[expect(v2)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWriteProperty[expect(v2)]" -Drat.skip=true
```

* Test shouldReadWriteProperty[expect(v3)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWriteProperty[expect(v3)]" -Drat.skip=true
```

* Test shouldReadWriteTraverser[expect(v2)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWriteTraverser[expect(v2)]" -Drat.skip=true
```

* Test shouldReadWriteTraverser[expect(v3)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWriteTraverser[expect(v3)]" -Drat.skip=true
```

* Test shouldReadWriteVertexProperty[expect(v2)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWriteVertexProperty[expect(v2)]" -Drat.skip=true
```

* Test shouldReadWriteVertexProperty[expect(v3)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWriteVertexProperty[expect(v3)]" -Drat.skip=true
```

* Test shouldReadWriteVertex[expect(v2)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWriteVertex[expect(v2)]" -Drat.skip=true
```

* Test shouldReadWriteVertex[expect(v3)]
```bash
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONTypedCompatibilityTest#shouldReadWriteVertex[expect(v3)]" -Drat.skip=true
```
And the error should be something like this:
```
[ERROR] Failures:
[ERROR]   GraphSONTypedCompatibilityTest>AbstractTypedCompatibilityTest.shouldReadWriteEdge:322 expected:<e[17][7-develops->10]> but was:<e[13][1-develops->10]>
[ERROR]   GraphSONTypedCompatibilityTest>AbstractTypedCompatibilityTest.shouldReadWriteEdge:322 expected:<e[17][7-develops->10]> but was:<e[13][1-develops->10]>
```

Upon our investigation, the root cause is the use of:
```
protected Map<Object, Vertex> vertices = new ConcurrentHashMap<>();
protected Map<Object, Edge> edges = new ConcurrentHashMap<>();
```
in TinkerGraph.java, which does not guarantee a deterministic order.

The simplest fix would be to replace ConcurrentHashMap with LinkedHashMap, as we did in a previous PR. We've confirmed that this change could remove the flakiness of these tests. However, we are concerned that such a change might introduce unintended side effects in the code under test. Another possible fix would be to deterministically select a fixed id, but that approach would make the test become sensitive to future implementation changes. Thus, we decided to use this sorting-based approach to deflake this test.

This fix also deflakes the entire GraphSONUntypedCompatibilityTest and GraphBinaryCompatibilityTest, which used to fail under NonDex in the 3.7-dev branch, this could be verified by:
```
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphson.GraphSONUntypedCompatibilityTest" -Drat.skip=true
```
```
mvn clean -pl gremlin-util edu.illinois:nondex-maven-plugin:2.2.1:nondex -Dtest="org.apache.tinkerpop.gremlin.structure.io.graphbinary.GraphBinaryCompatibilityTest" -Drat.skip=true
```

Co-authored-by: Siddhi Jhunjhunwala <[email protected]>

Author: KangweiZhu

gremlin-util/src/test/java/org/apache/tinkerpop/gremlin/structure/io/Model.java

@@ -40,6 +40,7 @@
 import org.apache.tinkerpop.gremlin.structure.VertexProperty;
 import org.apache.tinkerpop.gremlin.tinkergraph.structure.TinkerFactory;
 import org.apache.tinkerpop.gremlin.tinkergraph.structure.TinkerGraph;
+import org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils;
 import org.apache.tinkerpop.gremlin.util.message.RequestMessage;
 import org.apache.tinkerpop.gremlin.util.message.ResponseMessage;
 
@@ -115,12 +116,24 @@ private Model() {
         addCoreEntry(new java.sql.Timestamp(1481750076295L), "Timestamp", "");
         addCoreEntry(UUID.fromString("41d2e28a-20a4-4ab0-b379-d810dede3786"), "UUID");
 
-        addGraphStructureEntry(graph.edges().next(), "Edge", "");
-        addGraphStructureEntry(g.V().out().out().path().next(), "Path", "");
-        addGraphStructureEntry(graph.edges().next().properties().next(), "Property", "");
+        addGraphStructureEntry(IteratorUtils.list(graph.edges()).stream()
+                .sorted((e1, e2) -> Integer.compare((Integer)e1.id(), (Integer)e2.id()))
+                .iterator().next(), "Edge", "");
+        addGraphStructureEntry(g.V().order().by(T.id).out().out().path().next(), "Path", "");
+        addGraphStructureEntry(IteratorUtils.list(IteratorUtils.list(graph.edges()).stream()
+                .sorted((e1, e2) -> Integer.compare((Integer)e1.id(), (Integer)e2.id()))
+                .iterator().next().properties()).stream()
+                .sorted((p1, p2) -> p1.key().compareTo(p2.key()))
+                .iterator().next(), "Property", "");
         addGraphStructureEntry(graph, "TinkerGraph", "`TinkerGraph` has a custom serializer that is registered as part of the `TinkerIoRegistry`.");
-        addGraphStructureEntry(graph.vertices().next(), "Vertex", "");
-        addGraphStructureEntry(graph.vertices().next().properties().next(), "VertexProperty", "");
+        addGraphStructureEntry(IteratorUtils.list(graph.vertices()).stream()
+                .sorted((v1, v2) -> Integer.compare((Integer)v1.id(), (Integer)v2.id()))
+                .iterator().next(), "Vertex", "");
+        addGraphStructureEntry(IteratorUtils.list(IteratorUtils.list(graph.vertices()).stream()
+                .sorted((v1, v2) -> Integer.compare((Integer)v1.id(), (Integer)v2.id()))
+                .iterator().next().properties()).stream()
+                .sorted((p1, p2) -> Long.compare((Long)p1.id(), (Long)p2.id()))
+                .iterator().next(), "VertexProperty", "");
 
         addGraphProcessEntry(SackFunctions.Barrier.normSack, "Barrier", "");
         addGraphProcessEntry(new Bytecode.Binding("x", 1), "Binding", "A \"Binding\" refers to a `Bytecode.Binding`.");
@@ -153,7 +166,7 @@ private Model() {
         // TextP was only added at 3.4.0 and is not supported with untyped GraphSON of any sort
         addGraphProcessEntry(TextP.containing("ark"), "TextP", "");
         addGraphProcessEntry(createStaticTraversalMetrics(), "TraversalMetrics", "");
-        addGraphProcessEntry(g.V().hasLabel("person").asAdmin().nextTraverser(), "Traverser", "");
+        addGraphProcessEntry(g.V().hasLabel("person").order().by(T.id).asAdmin().nextTraverser(), "Traverser", "");
 
         final Map<String,Object> requestBindings = new HashMap<>();
         requestBindings.put("x", 1);
@@ -192,7 +205,9 @@ private Model() {
         addResponseMessageEntry(responseMessage, "Authentication Challenge", "When authentication is enabled, an initial request to the server will result in an authentication challenge. The typical response message will appear as follows, but handling it could be different depending on the SASL implementation (e.g. multiple challenges maybe requested in some cases, but not in the default provided by Gremlin Server).");
         responseMessage = ResponseMessage.build(UUID.fromString("41d2e28a-20a4-4ab0-b379-d810dede3786")).
                 code(org.apache.tinkerpop.gremlin.util.message.ResponseStatusCode.SUCCESS).
-                result(Collections.singletonList(graph.vertices().next())).create();
+                result(Collections.singletonList(IteratorUtils.list(graph.vertices()).stream()
+                        .sorted((v1, v2) -> Integer.compare((Integer)v1.id(), (Integer)v2.id()))
+                        .iterator().next())).create();
         addResponseMessageEntry(responseMessage, "Standard Result", "The following `ResponseMessage` is a typical example of the typical successful response Gremlin Server will return when returning results from a script.");
 
         addExtendedEntry(new BigDecimal(new BigInteger("123456789987654321123456789987654321")), "BigDecimal", "");