then:
        versions == ["1.2", "1.3", "1.3", "1.4"] as Set

        and:
        1 * repo.resource(new ExternalResourceName("/")) >> resource1
        1 * resource1.list() >> ["1.2", "1.3"]
        1 * repo.resource(new ExternalResourceName("/org.acme/")) >> resource2
        1 * resource2.list() >> ["1.3", "1.4"]
        0 * _
    }

     */
    ExternalResourceName toVersionListPattern(ModuleIdentifier module, IvyArtifactName artifact);

    /**
     * Returns the path for the given module.
     */
    ExternalResourceName toModulePath(ModuleIdentifier moduleIdentifier);

    /**
     * Returns the path for the given component.
     */
    ExternalResourceName toModuleVersionPath(ModuleComponentIdentifier componentIdentifier);

    }

    @Nullable
    @Override
    public List<String> list(ExternalResourceName parent) throws ResourceException {
        LOGGER.debug("Listing parent resources: {}", parent);
        return gcsClient.list(parent.getUri());
    }

    @Nullable
    @Override
    public ExternalResourceReadResponse openResource(ExternalResourceName location, boolean revalidate) throws ResourceException {

import org.gradle.api.internal.file.temp.TemporaryFileProvider;
import org.gradle.cache.internal.ProducerGuard;
import org.gradle.internal.hash.ChecksumService;
import org.gradle.internal.resource.ExternalResourceName;
import org.gradle.internal.resource.ExternalResourceRepository;
import org.gradle.internal.resource.cached.CachedExternalResourceIndex;
import org.gradle.internal.resource.local.FileResourceRepository;

        final Set<ExternalResourceName> searched = new HashSet<>();

        List<String> versions = new ArrayList<>();
        boolean hasResult = false;
        for (ResourcePattern pattern : patterns) {
            ExternalResourceName metadataLocation = pattern.toModulePath(module).resolve("maven-metadata.xml");

 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.gradle.internal.resolve.result;

import org.gradle.internal.resource.ExternalResourceName;

import java.util.List;

public interface ResourceAwareResolveResult {
    List<String> getAttempted();

    /**

    }

    @Override
    public LocallyAvailableExternalResource resource(ExternalResourceName resource, boolean revalidate) {
        return resource(resource);
    }

    @Override
    public LocallyAvailableExternalResource resource(ExternalResourceName location) {
        File localFile = getFile(location);

 * limitations under the License.
 */

package org.gradle.internal.resource.transport.http;

import org.gradle.api.resources.ResourceException;
import org.gradle.internal.resource.ExternalResourceName;
import org.gradle.internal.resource.transfer.ExternalResourceLister;

import java.util.List;

public class HttpResourceLister implements ExternalResourceLister {
    private final HttpResourceAccessor accessor;

    public AbstractResourcePattern(String pattern) {
        this(new ExternalResourceName(pattern));

    }

    public AbstractResourcePattern(URI baseUri, String pattern) {
        this(new ExternalResourceName(baseUri, pattern));
    }

    private AbstractResourcePattern(ExternalResourceName pattern) {
        this.pattern = pattern;

import org.gradle.internal.resource.ExternalResourceName;
import org.gradle.internal.resource.ResourceExceptions;

import javax.annotation.Nullable;
import java.io.IOException;
import java.io.InputStream;

public abstract class AbstractExternalResourceAccessor implements ExternalResourceAccessor {
    @Nullable
    @Override