gremlin-test/src/main/java/org/apache/tinkerpop/gremlin/process/traversal/strategy/decoration/PartitionStrategyProcessTest.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
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package org.apache.tinkerpop.gremlin.process.traversal.strategy.decoration;

import org.apache.commons.configuration2.MapConfiguration;
import org.apache.tinkerpop.gremlin.FeatureRequirement;
import org.apache.tinkerpop.gremlin.FeatureRequirementSet;
import org.apache.tinkerpop.gremlin.process.AbstractGremlinProcessTest;
import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversalSource;
import org.apache.tinkerpop.gremlin.structure.Edge;
import org.apache.tinkerpop.gremlin.structure.Graph;
import org.apache.tinkerpop.gremlin.structure.Vertex;
import org.apache.tinkerpop.gremlin.structure.VertexProperty;
import org.apache.tinkerpop.gremlin.util.iterator.IteratorUtils;
import org.junit.Test;

import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.NoSuchElementException;
import java.util.stream.Collectors;

import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.Matchers.containsInAnyOrder;
import static org.hamcrest.core.IsInstanceOf.instanceOf;
import static org.hamcrest.core.StringStartsWith.startsWith;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotNull;
import static org.hamcrest.MatcherAssert.assertThat;
import static org.junit.Assert.fail;

/**
 * @author Stephen Mallette (http://stephen.genoprime.com)
 */
public class PartitionStrategyProcessTest extends AbstractGremlinProcessTest {
    private static final String partition = "gremlin.partitionGraphStrategy.partition";

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    public void shouldAppendPartitionToVertex() {
        final PartitionStrategy partitionStrategy = PartitionStrategy.build()
                .partitionKey(partition).writePartition("A").readPartitions("A").create();
        final Vertex v = g.withStrategies(partitionStrategy).addV().property("any", "thing").next();

        assertNotNull(v);
        assertEquals("thing", g.V(v).values("any").next());
        assertEquals("A", g.V(v).values(partition).next());
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldAppendPartitionToVertexProperty() {
        final PartitionStrategy partitionStrategy = PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create();
        final Vertex v = g.withStrategies(partitionStrategy).addV().property("any", "thing").next();

        assertNotNull(v);
        assertEquals("thing", g.V(v).values("any").next());
        assertEquals("A", g.V(v).values(partition).next());
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_MULTI_PROPERTIES)
    public void shouldAppendPartitionToVertexPropertyOverMultiProperty() {
        final PartitionStrategy partitionStrategy = PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create();
        final Vertex v = g.withStrategies(partitionStrategy).addV().property(VertexProperty.Cardinality.list, "any", "thing")
                .property(VertexProperty.Cardinality.list, "any", "more").next();

        assertNotNull(v);
        assertThat((List<String>) IteratorUtils.asList(g.V(v).properties("any")).stream().map(p -> ((VertexProperty) p).value()).collect(Collectors.toList()), containsInAnyOrder("thing", "more"));
        assertEquals("A", v.property(partition).value());
        assertThat((List<String>) IteratorUtils.asList(g.V(v).properties("any")).stream().map(p -> ((VertexProperty) p).value(partition)).collect(Collectors.toList()), containsInAnyOrder("A", "A"));
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldNotAppendPartitionToVertexProperty() {
        final PartitionStrategy partitionStrategy = PartitionStrategy.build()
                .includeMetaProperties(false)
                .partitionKey(partition).writePartition("A").readPartitions("A").create();
        final Vertex v = g.withStrategies(partitionStrategy).addV().property("any", "thing").next();

        assertNotNull(v);
        assertEquals("thing", g.V(v).values("any").next());
        assertEquals("A", g.V(v).values(partition).next());
        assertThat(g.V(v).properties("any").properties().hasNext(), is(false));

    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldAppendPartitionToAllVertexProperties() {
        final GraphTraversalSource gOverA = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create());

        final GraphTraversalSource gOverB = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("B").readPartitions("B").create());

        final GraphTraversalSource gOverAB = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("B").readPartitions("B","A").create());

        final Vertex v = gOverA.addV().property("any", "thing").property("some", "thing").next();
        final Vertex labelledV = gOverA.addV("person").property("name", "thing").property("that", "thing").next();

        assertNotNull(v);
        assertEquals("thing", g.V(v).values("any").next());
        assertEquals(Vertex.DEFAULT_LABEL, g.V(v).label().next());
        assertEquals("A", g.V(v).values(partition).next());
        assertEquals("A", g.V(v).properties("any").values(partition).next());
        assertEquals("thing", g.V(v).values("some").next());
        assertEquals("A", g.V(v).properties("some").values(partition).next());

        assertNotNull(labelledV);
        assertEquals("thing", g.V(labelledV).values("name").next());
        assertEquals("person", g.V(labelledV).label().next());
        assertEquals("A", g.V(labelledV).values(partition).next());
        assertEquals("A", g.V(labelledV).properties("name").values(partition).next());
        assertEquals("thing", g.V(labelledV).values("that").next());
        assertEquals("A", g.V(labelledV).properties("that").values(partition).next());

        gOverAB.V(v).property("that", "thing").iterate();
        assertEquals("thing", g.V(v).values("that").next());
        assertEquals("B", g.V(v).properties("that").values(partition).next());

        assertThat(gOverAB.V(v).properties("any").hasNext(), is(true));
        assertThat(gOverAB.V(v).properties("that").hasNext(), is(true));
        assertThat(gOverA.V(v).properties("that").hasNext(), is(false));
        assertThat(gOverA.V(v).properties("any").hasNext(), is(true));
        assertThat(gOverB.V(v).properties("any").hasNext(), is(false));
        assertThat(gOverB.V(v).properties("that").hasNext(), is(false));
        assertThat(gOverAB.V(v).properties("partitionKey").hasNext(), is(false));

        assertThat(gOverAB.V(v).values("any").hasNext(), is(true));
        assertThat(gOverAB.V(v).values("that").hasNext(), is(true));
        assertThat(gOverA.V(v).values("that").hasNext(), is(false));
        assertThat(gOverA.V(v).values("any").hasNext(), is(true));
        assertThat(gOverB.V(v).values("any").hasNext(), is(false));
        assertThat(gOverB.V(v).values("that").hasNext(), is(false));
        assertThat(gOverAB.V(v).values("partitionKey").hasNext(), is(false));

        assertThat(gOverAB.V(v).propertyMap().next().containsKey("any"), is(true));
        assertThat(gOverAB.V(v).propertyMap().next().containsKey("that"), is(true));
        assertThat(gOverA.V(v).propertyMap().next().containsKey("that"), is(false));
        assertThat(gOverA.V(v).propertyMap().next().containsKey("any"), is(true));
        assertThat(gOverB.V(v).propertyMap().hasNext(), is(false));
        assertThat(gOverB.V(v).propertyMap().hasNext(), is(false));
        assertThat(gOverAB.V(v).propertyMap().next().containsKey(partition), is(false));

        assertThat(gOverAB.V(v).valueMap().next().containsKey("any"), is(true));
        assertThat(gOverAB.V(v).valueMap().next().containsKey("that"), is(true));
        assertThat(gOverA.V(v).valueMap().next().containsKey("that"), is(false));
        assertThat(gOverA.V(v).valueMap().next().containsKey("any"), is(true));
        assertThat(gOverB.V(v).valueMap().hasNext(), is(false));
        assertThat(gOverB.V(v).valueMap().hasNext(), is(false));
        assertThat(gOverAB.V(v).valueMap().next().containsKey(partition), is(false));
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldHidePartitionKeyForValues() {
        final GraphTraversalSource gOverA = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create());
        final Vertex v = gOverA.addV().property("any", "thing").next();

        try {
            gOverA.V(v).values(partition).next();
            fail("Should have thrown exception");
        } catch (Exception ex) {
            assertThat(ex.getMessage(), startsWith("Cannot explicitly request the partitionKey in the traversal"));
        }

    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldHidePartitionKeyForValuesWithEmptyKeys() {
        final GraphTraversalSource gOverA = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create());
        final Vertex v = gOverA.addV().property("any", "thing").next();

        assertEquals(1L, (long) gOverA.V(v).values().count().next());
        assertEquals("thing", gOverA.V(v).values().next());
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldHidePartitionKeyForProperties() {
        final GraphTraversalSource gOverA = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create());
        final Vertex v = gOverA.addV().property("any", "thing").next();

        try {
            gOverA.V(v).properties(partition).next();
            fail("Should have thrown exception");
        } catch (Exception ex) {
            assertThat(ex.getMessage(), startsWith("Cannot explicitly request the partitionKey in the traversal"));
        }
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldHidePartitionKeyForPropertiesWithEmptyKeys() {
        final GraphTraversalSource gOverA = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create());
        final Vertex v = gOverA.addV().property("any", "thing").next();

        assertEquals(1L, (long) gOverA.V(v).properties().count().next());
        assertEquals("thing", gOverA.V(v).properties().value().next());
    }

    @Test(expected = IllegalStateException.class)
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldHidePartitionKeyForPropertyMap() {
        final GraphTraversalSource gOverA = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create());
        final Vertex v = gOverA.addV().property("any", "thing").next();

        gOverA.V(v).propertyMap(partition).next();
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldHidePartitionKeyForPropertyMapWithEmptyKeys() {
        final GraphTraversalSource gOverA = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create());
        final Vertex v = gOverA.addV().property("any", "thing").next();

        assertEquals(1L, (long) gOverA.V(v).propertyMap().count().next());
        assertEquals("thing", ((List<VertexProperty>) gOverA.V(v).propertyMap().next().get("any")).get(0).value());
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldHidePartitionKeyForValueMap() {
        final GraphTraversalSource gOverA = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create());
        final Vertex v = gOverA.addV().property("any", "thing").next();

        try {
            gOverA.V(v).valueMap(partition).next();
            fail("Should have thrown exception");
        } catch (Exception ex) {

        }
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    @FeatureRequirement(featureClass = Graph.Features.VertexFeatures.class, feature = Graph.Features.VertexFeatures.FEATURE_META_PROPERTIES)
    public void shouldHidePartitionKeyForValueMapWithEmptyKeys() {
        final GraphTraversalSource gOverA = g.withStrategies(PartitionStrategy.build()
                .includeMetaProperties(true)
                .partitionKey(partition).writePartition("A").readPartitions("A").create());
        final Vertex v = gOverA.addV().property("any", "thing").next();

        assertEquals(1L, (long) gOverA.V(v).valueMap().count().next());
        assertEquals("thing", ((List) gOverA.V(v).valueMap().next().get("any")).get(0));
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.SIMPLE)
    public void shouldAppendPartitionToEdge() {
        final PartitionStrategy partitionStrategy = PartitionStrategy.build()
                .partitionKey(partition).writePartition("A").readPartitions("A").create();
        final GraphTraversalSource source = g.withStrategies(partitionStrategy);
        final Vertex v1 = source.addV().property("any", "thing").next();
        final Vertex v2 = source.addV().property("some", "thing").next();
        final Edge e1 = source.V(v1).addE("connectsTo").from(v2).property("every", "thing").next();
        final Edge e2 = source.addE("relatesTo").from(v2).to(v1).property("every", "thing").next();

        assertNotNull(v1);
        assertEquals("thing", g.V(v1).values("any").next());
        assertEquals("A", g.V(v2).values(partition).next());

        assertNotNull(v2);
        assertEquals("thing", g.V(v2).values("some").next());
        assertEquals("A", g.V(v2).values(partition).next());

        assertNotNull(e1);
        assertEquals("thing", g.E(e1).values("every").next());
        assertEquals("connectsTo", e1.label());
        assertEquals("A", g.E(e1).values(partition).next());

        assertNotNull(e2);
        assertEquals("thing", g.E(e2).values("every").next());
        assertEquals("relatesTo", e2.label());
        assertEquals("A", g.E(e2).values(partition).next());
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    public void shouldWriteVerticesToMultiplePartitions() {
        final PartitionStrategy partitionStrategyAA = PartitionStrategy.build()
                .partitionKey(partition).writePartition("A").readPartitions("A").create();
        final GraphTraversalSource sourceAA = g.withStrategies(partitionStrategyAA);

        final PartitionStrategy partitionStrategyBA = PartitionStrategy.build()
                .partitionKey(partition).writePartition("B").readPartitions("A").create();
        final GraphTraversalSource sourceBA = g.withStrategies(partitionStrategyBA);

        final PartitionStrategy partitionStrategyBB = PartitionStrategy.build()
                .partitionKey(partition).writePartition("B").readPartitions("B").create();
        final GraphTraversalSource sourceBB = g.withStrategies(partitionStrategyBB);

        final PartitionStrategy partitionStrategyBAB = PartitionStrategy.build()
                .partitionKey(partition).writePartition("B").readPartitions("A", "B").create();
        final GraphTraversalSource sourceBAB = g.withStrategies(partitionStrategyBAB);


        final Vertex vA = sourceAA.addV().property("any", "a").next();
        final Vertex vB = sourceBA.addV().property("any", "b").next();

        assertNotNull(vA);
        assertEquals("a", g.V(vA).values("any").next());
        assertEquals("A", g.V(vA).values(partition).next());

        assertNotNull(vB);
        assertEquals("b", g.V(vB).values("any").next());
        assertEquals("B", g.V(vB).values(partition).next());

        sourceBA.V().forEachRemaining(v -> assertEquals("a", g.V(v).values("any").next()));
        sourceBB.V().forEachRemaining(v -> assertEquals("b", g.V(v).values("any").next()));

        assertEquals(new Long(2), sourceBAB.V().count().next());
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.VERTICES_ONLY)
    public void shouldThrowExceptionOnVInDifferentPartition() {
        final PartitionStrategy partitionStrategyAA = PartitionStrategy.build()
                .partitionKey(partition).writePartition("A").readPartitions("A").create();
        final GraphTraversalSource sourceAA = g.withStrategies(partitionStrategyAA);

        final PartitionStrategy partitionStrategyA = PartitionStrategy.build()
                .partitionKey(partition).writePartition("A").create();
        final GraphTraversalSource sourceA = g.withStrategies(partitionStrategyA);

        final Vertex vA = sourceAA.addV().property("any", "a").next();
        assertEquals(vA.id(), sourceAA.V(vA.id()).id().next());

        try {
            sourceA.V(vA.id()).next();
            fail("Vertex should not be in this partition");
        } catch (Exception ex) {
            assertThat(ex, instanceOf(NoSuchElementException.class));
        }
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.SIMPLE)
    public void shouldThrowExceptionOnEInDifferentPartition() {
        final PartitionStrategy partitionStrategyAA = PartitionStrategy.build()
                .partitionKey(partition).writePartition("A").readPartitions("A").create();
        final GraphTraversalSource sourceAA = g.withStrategies(partitionStrategyAA);

        final PartitionStrategy partitionStrategyA = PartitionStrategy.build()
                .partitionKey(partition).writePartition("A").create();
        final GraphTraversalSource sourceA = g.withStrategies(partitionStrategyA);

        final Vertex vA = sourceAA.addV().property("any", "a").next();
        final Edge e = sourceAA.withSideEffect("vA", vA).V(vA.id()).addE("knows").to("vA").next();
        assertEquals(e.id(), g.E(e.id()).id().next());

        try {
            sourceA.E(e.id()).next();
            fail("Edge should not be in this partition");
        } catch (Exception ex) {
            assertEquals(NoSuchElementException.class, ex.getClass());
        }
    }

    @Test
    @FeatureRequirementSet(FeatureRequirementSet.Package.SIMPLE)
    public void shouldWriteToMultiplePartitions() {
        final PartitionStrategy partitionStrategyAA = PartitionStrategy.build()
                .partitionKey(partition).writePartition("A").readPartitions("A").create();
        final GraphTraversalSource sourceAA = g.withStrategies(partitionStrategyAA);

        final PartitionStrategy partitionStrategyBA = PartitionStrategy.build()
                .partitionKey(partition).writePartition("B").readPartitions("A").create();
        final GraphTraversalSource sourceBA = g.withStrategies(partitionStrategyBA);

        final PartitionStrategy partitionStrategyCAB = PartitionStrategy.build()
                .partitionKey(partition).writePartition("C").readPartitions("A","B").create();
        final GraphTraversalSource sourceCAB = g.withStrategies(partitionStrategyCAB);

        final PartitionStrategy partitionStrategyC = PartitionStrategy.build()
                .partitionKey(partition).writePartition("C").create();
        final GraphTraversalSource sourceC = g.withStrategies(partitionStrategyC);

        final PartitionStrategy partitionStrategyCA = PartitionStrategy.build()
                .partitionKey(partition).writePartition("C").readPartitions("A").create();
        final GraphTraversalSource sourceCA = g.withStrategies(partitionStrategyCA);

        final GraphTraversalSource sourceCABC = g.withStrategies(PartitionStrategy.create(new MapConfiguration(new HashMap<String, Object>() {{

            put(PartitionStrategy.WRITE_PARTITION, "C");
            put(PartitionStrategy.PARTITION_KEY, partition);
            put(PartitionStrategy.READ_PARTITIONS, Arrays.asList("A", "B", "C"));
        }})));
        final PartitionStrategy partitionStrategyCC = PartitionStrategy.build()
                .partitionKey(partition).writePartition("C").readPartitions("C").create();
        final GraphTraversalSource sourceCC = g.withStrategies(partitionStrategyCC);

        final PartitionStrategy partitionStrategyCBC = PartitionStrategy.build()
                .partitionKey(partition).writePartition("C").readPartitions(Arrays.asList("B", "C")).create();
        final GraphTraversalSource sourceCBC = g.withStrategies(partitionStrategyCBC);

        final Vertex vA = sourceAA.addV().property("any", "a").next();
        final Vertex vAA = sourceAA.addV().property("any", "aa").next();
        final Edge eAtoAA = sourceAA.withSideEffect("vAA", vAA).V(vA.id()).addE("aTOa").to("vAA").next();

        final Vertex vB = sourceBA.addV().property("any", "b").next();
        sourceBA.withSideEffect("vB", vB).V(vA.id()).addE("aTOb").to("vB").next();

        final Vertex vC = sourceCAB.addV().property("any", "c").next();
        final Edge eBtovC = sourceCAB.withSideEffect("vC", vC).V(vB.id()).addE("bTOc").to("vC").next();
        final Edge eAtovC = sourceCAB.withSideEffect("vC", vC).V(vA.id()).addE("aTOc").to("vC").next();

        assertEquals(0, IteratorUtils.count(sourceC.V()));
        assertEquals(0, IteratorUtils.count(sourceC.E()));

        assertEquals(new Long(2), sourceCA.V().count().next());
        assertEquals(new Long(1), sourceCA.E().count().next());
        assertEquals(new Long(1), sourceCA.V(vA.id()).outE().count().next());
        assertEquals(eAtoAA.id(), sourceCA.V(vA.id()).outE().next().id());
        assertEquals(new Long(1), sourceCA.V(vA.id()).out().count().next());
        assertEquals(vAA.id(), sourceCA.V(vA.id()).out().next().id());

        final Vertex vA1 = sourceCA.V(vA.id()).next();
        assertEquals(new Long(1), sourceCA.V(vA1).outE().count().next());
        assertEquals(eAtoAA.id(), sourceCA.V(vA1).outE().next().id());
        assertEquals(new Long(1), sourceCA.V(vA1).out().count().next());
        assertEquals(vAA.id(), sourceCA.V(vA1).out().next().id());

        assertEquals(new Long(3), sourceCAB.V().count().next());
        assertEquals(new Long(2), sourceCAB.E().count().next());

        assertEquals(new Long(4), sourceCABC.V().count().next());
        assertEquals(new Long(4), sourceCABC.E().count().next());

        assertEquals(1, IteratorUtils.count(sourceCC.V()));
        // two edges are in the "C" partition, but one each of their incident vertices are not
        assertEquals(2, IteratorUtils.count(sourceCC.E()));

        // two edges are in the "C" partition, but one each of their incident vertices are not
        assertEquals(new Long(2), sourceCC.V(vC.id()).inE().count().next());
        assertEquals(new Long(0), sourceCC.V(vC.id()).in().count().next());

        // excluded vertices; vA is not in {B,C}
        assertEquals(new Long(2), sourceCBC.V(vC.id()).inE().count().next());
        assertEquals(new Long(1), sourceCBC.V(vC.id()).in().count().next());
        assertEquals(vC.id(), sourceCBC.E(eBtovC.id()).inV().id().next());
        assertEquals(vB.id(), sourceCBC.E(eBtovC.id()).outV().id().next());
        assertEquals(vC.id(), sourceCBC.E(eAtovC.id()).inV().id().next());
        assertFalse(sourceCBC.E(eAtovC.id()).outV().hasNext());
    }
}