1 * visitor.visitArtifact(artifact1)
        0 * _

        when:
        set2.artifacts.visitTransformSources(visitor)

        then:
        1 * artifact1.id >> new ComponentFileArtifactIdentifier(Stub(ProjectComponentIdentifier), "some-file")
        1 * visitor.visitArtifact(artifact1)
        0 * _
    }

    def "collects build dependencies"() {

     */
    void visitArtifact(DisplayName variantName, AttributeContainer variantAttributes, ImmutableCapabilities capabilities, ResolvableArtifact artifact);

    /**
     * Should the file for each artifact be made available prior to calling {@link #visitArtifact(DisplayName, AttributeContainer, ImmutableCapabilities, ResolvableArtifact)}?
     *

        1 * artifactTypeRegistry.mapAttributesFor(f2) >> attrs2

        then:
        1 * visitor.visitArtifacts(_) >> { ResolvedArtifactSet.Artifacts artifacts -> artifacts.visit(artifactVisitor) }

    def "adds expensive artifact transformations to the build operation queue"() {
        when:
        listener.visitArtifacts(artifacts)
        def artifacts = result.build()

        then:
        artifacts.size() == 1
        1 * artifacts.visit(_) >> { ArtifactVisitor visitor -> visitor.visitArtifact(null, null, ImmutableCapabilities.EMPTY, artifact) }
        0 * _

        when:

                visitor.visitFailure(artifact.getFileSource().getValue().getFailure().get());
            } else {
                visitor.visitArtifact(variantName, variantAttributes, capabilities, artifact);
                visitor.endVisitCollection(FileCollectionInternal.OTHER);
            }
        }

        @Override

        this.capabilities = capabilities;
        this.result = result;
    }

    @Override
    public void visitArtifacts(ResolvedArtifactSet.Artifacts artifacts) {
        artifacts.visit(new ArtifactVisitor() {
            @Override
            public void visitArtifact(DisplayName variantName, AttributeContainer variantAttributes, ImmutableCapabilities variantCapabilities, ResolvableArtifact artifact) {

        FileCollectionStructureVisitor.VisitType visitType = visitor.prepareForVisit(this);
        if (visitType == FileCollectionStructureVisitor.VisitType.NoContents) {
            visitor.visitArtifacts(new EndCollection(this));
        } else {
            visitor.visitArtifacts(this);
        }
    }

    @Override
    public void startFinalization(BuildOperationQueue<RunnableBuildOperation> actions, boolean requireFiles) {

        return visitor.prepareForVisit(source);
    }

    public void visitFile(File file) {
        visitor.visitFile(file);
    }

    @Override
    public void visitArtifact(DisplayName variantName, AttributeContainer variantAttributes, ImmutableCapabilities capabilities, ResolvableArtifact artifact) {
        visitor.visitFile(artifact.getFile());
    }

    @Override

    @Override
    public void visitFailure(Throwable failure) {
        failures.add(failure);
    }

    @Override
    public void visitArtifact(DisplayName variantName, AttributeContainer variantAttributes, ImmutableCapabilities capabilities, ResolvableArtifact artifact) {
        try {
            if (seenArtifacts.add(artifact.getId())) {

    private final Set<File> files = new LinkedHashSet<>();
    private final Set<Throwable> failures = new LinkedHashSet<>();

    @Override
    public void visitArtifact(DisplayName variantName, AttributeContainer variantAttributes, ImmutableCapabilities capabilities, ResolvableArtifact artifact) {
        try {
            File file = artifact.getFile();
            this.files.add(file);