gremlin-core/src/test/java/org/apache/tinkerpop/gremlin/process/util/TraversalHelperTest.java

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 * 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
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package org.apache.tinkerpop.gremlin.process.util;

import org.apache.tinkerpop.gremlin.process.traversal.Step;
import org.apache.tinkerpop.gremlin.process.traversal.Traversal;
import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.__;
import org.apache.tinkerpop.gremlin.process.traversal.step.Mutating;
import org.apache.tinkerpop.gremlin.process.traversal.step.filter.DropStep;
import org.apache.tinkerpop.gremlin.process.traversal.step.filter.FilterStep;
import org.apache.tinkerpop.gremlin.process.traversal.step.filter.HasStep;
import org.apache.tinkerpop.gremlin.process.traversal.step.filter.LambdaFilterStep;
import org.apache.tinkerpop.gremlin.process.traversal.step.filter.TraversalFilterStep;
import org.apache.tinkerpop.gremlin.process.traversal.step.map.AddVertexStartStep;
import org.apache.tinkerpop.gremlin.process.traversal.step.map.PropertiesStep;
import org.apache.tinkerpop.gremlin.process.traversal.step.sideEffect.IdentityStep;
import org.apache.tinkerpop.gremlin.process.traversal.util.DefaultTraversal;
import org.apache.tinkerpop.gremlin.process.traversal.step.util.EmptyStep;
import org.apache.tinkerpop.gremlin.process.traversal.util.TraversalHelper;
import org.apache.tinkerpop.gremlin.structure.PropertyType;
import org.apache.tinkerpop.gremlin.structure.util.empty.EmptyGraph;
import org.junit.Test;
import org.mockito.Mockito;

import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.*;

/**
 * @author Marko A. Rodriguez (http://markorodriguez.com)
 * @author Stephen Mallette (http://stephen.genoprime.com)
 */
public class TraversalHelperTest {

    @Test
    public void shouldNotFindStepOfClassInTraversal() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, new HasStep(traversal));

        assertThat(TraversalHelper.hasStepOfClass(FilterStep.class, traversal), is(false));
    }

    @Test
    public void shouldFindStepOfClassInTraversal() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, new IdentityStep<>(traversal));
        traversal.asAdmin().addStep(0, new HasStep(traversal));

        assertThat(TraversalHelper.hasStepOfClass(IdentityStep.class, traversal), is(true));
    }

    @Test
    public void shouldNotFindStepOfAssignableClassInTraversal() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, new HasStep(traversal));

        assertThat(TraversalHelper.hasStepOfAssignableClass(IdentityStep.class, traversal), is(false));
    }

    @Test
    public void shouldFindStepOfAssignableClassInTraversal() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, new HasStep(traversal));

        assertThat(TraversalHelper.hasStepOfAssignableClass(FilterStep.class, traversal), is(true));
    }

    @Test
    public void shouldGetTheStepIndex() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        final HasStep hasStep = new HasStep(traversal);
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, hasStep);
        traversal.asAdmin().addStep(0, new HasStep(traversal));

        assertEquals(1, TraversalHelper.stepIndex(hasStep, traversal));
    }

    @Test
    public void shouldNotFindTheStepIndex() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        final IdentityStep identityStep = new IdentityStep(traversal);
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, new HasStep(traversal));

        assertEquals(-1, TraversalHelper.stepIndex(identityStep, traversal));
    }

    @Test
    public void shouldInsertBeforeStep() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        final HasStep hasStep = new HasStep(traversal);
        final IdentityStep identityStep = new IdentityStep(traversal);
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, hasStep);
        traversal.asAdmin().addStep(0, new HasStep(traversal));

        TraversalHelper.insertBeforeStep(identityStep, hasStep, traversal);

        assertEquals(traversal.asAdmin().getSteps().get(1), identityStep);
        assertEquals(4, traversal.asAdmin().getSteps().size());
    }

    @Test
    public void shouldInsertAfterStep() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        final HasStep hasStep = new HasStep(traversal);
        final IdentityStep identityStep = new IdentityStep(traversal);
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, hasStep);
        traversal.asAdmin().addStep(0, new HasStep(traversal));

        TraversalHelper.insertAfterStep(identityStep, hasStep, traversal);

        assertEquals(traversal.asAdmin().getSteps().get(2), identityStep);
        assertEquals(4, traversal.asAdmin().getSteps().size());
    }

    @Test
    public void shouldReplaceStep() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        final HasStep hasStep = new HasStep(traversal);
        final IdentityStep identityStep = new IdentityStep(traversal);
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, hasStep);
        traversal.asAdmin().addStep(0, new HasStep(traversal));

        TraversalHelper.replaceStep(hasStep, identityStep, traversal);

        assertEquals(traversal.asAdmin().getSteps().get(1), identityStep);
        assertEquals(3, traversal.asAdmin().getSteps().size());
    }

    @Test
    public void shouldChainTogetherStepsWithNextPreviousInALinkedListStructure() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        traversal.asAdmin().addStep(new IdentityStep(traversal));
        traversal.asAdmin().addStep(new HasStep(traversal));
        traversal.asAdmin().addStep(new LambdaFilterStep(traversal, traverser -> true));
        validateToyTraversal(traversal);
    }

    @Test
    public void shouldAddStepsCorrectly() {
        Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        traversal.asAdmin().addStep(0, new LambdaFilterStep(traversal, traverser -> true));
        traversal.asAdmin().addStep(0, new HasStep(traversal));
        traversal.asAdmin().addStep(0, new IdentityStep(traversal));
        validateToyTraversal(traversal);

        traversal = new DefaultTraversal<>(EmptyGraph.instance());
        traversal.asAdmin().addStep(0, new IdentityStep(traversal));
        traversal.asAdmin().addStep(1, new HasStep(traversal));
        traversal.asAdmin().addStep(2, new LambdaFilterStep(traversal, traverser -> true));
        validateToyTraversal(traversal);
    }

    @Test
    public void shouldRemoveStepsCorrectly() {
        final Traversal.Admin traversal = new DefaultTraversal<>(EmptyGraph.instance());
        traversal.asAdmin().addStep(new IdentityStep(traversal));
        traversal.asAdmin().addStep(new HasStep(traversal));
        traversal.asAdmin().addStep(new LambdaFilterStep(traversal, traverser -> true));

        traversal.asAdmin().addStep(new PropertiesStep(traversal, PropertyType.VALUE, "marko"));
        traversal.asAdmin().removeStep(3);
        validateToyTraversal(traversal);

        traversal.asAdmin().addStep(0, new PropertiesStep(traversal, PropertyType.PROPERTY, "marko"));
        traversal.asAdmin().removeStep(0);
        validateToyTraversal(traversal);

        traversal.asAdmin().removeStep(1);
        traversal.asAdmin().addStep(1, new HasStep(traversal));
        validateToyTraversal(traversal);
    }

    private static void validateToyTraversal(final Traversal traversal) {
        assertEquals(traversal.asAdmin().getSteps().size(), 3);

        assertEquals(IdentityStep.class, traversal.asAdmin().getSteps().get(0).getClass());
        assertEquals(HasStep.class, traversal.asAdmin().getSteps().get(1).getClass());
        assertEquals(LambdaFilterStep.class, traversal.asAdmin().getSteps().get(2).getClass());

        // IDENTITY STEP
        assertEquals(EmptyStep.class, ((Step) traversal.asAdmin().getSteps().get(0)).getPreviousStep().getClass());
        assertEquals(HasStep.class, ((Step) traversal.asAdmin().getSteps().get(0)).getNextStep().getClass());
        assertEquals(LambdaFilterStep.class, ((Step) traversal.asAdmin().getSteps().get(0)).getNextStep().getNextStep().getClass());
        assertEquals(EmptyStep.class, ((Step) traversal.asAdmin().getSteps().get(0)).getNextStep().getNextStep().getNextStep().getClass());

        // HAS STEP
        assertEquals(IdentityStep.class, ((Step) traversal.asAdmin().getSteps().get(1)).getPreviousStep().getClass());
        assertEquals(EmptyStep.class, ((Step) traversal.asAdmin().getSteps().get(1)).getPreviousStep().getPreviousStep().getClass());
        assertEquals(LambdaFilterStep.class, ((Step) traversal.asAdmin().getSteps().get(1)).getNextStep().getClass());
        assertEquals(EmptyStep.class, ((Step) traversal.asAdmin().getSteps().get(1)).getNextStep().getNextStep().getClass());

        // FILTER STEP
        assertEquals(HasStep.class, ((Step) traversal.asAdmin().getSteps().get(2)).getPreviousStep().getClass());
        assertEquals(IdentityStep.class, ((Step) traversal.asAdmin().getSteps().get(2)).getPreviousStep().getPreviousStep().getClass());
        assertEquals(EmptyStep.class, ((Step) traversal.asAdmin().getSteps().get(2)).getPreviousStep().getPreviousStep().getPreviousStep().getClass());
        assertEquals(EmptyStep.class, ((Step) traversal.asAdmin().getSteps().get(2)).getNextStep().getClass());

        assertEquals(3, traversal.asAdmin().getSteps().size());
    }

    @Test
    public void shouldTruncateLongName() {
        Step s = Mockito.mock(Step.class);
        Mockito.when(s.toString()).thenReturn("0123456789");
        assertEquals("0123...", TraversalHelper.getShortName(s, 7));
    }
}