return kind;
    }

    public String getExpected() {
        return expected;
    }

    public String getActual() {
        return actual;
    }

    @Override
    public void explainTo(TreeFormatter formatter) {
        formatter.append("expected a '" + kind + "' checksum of '" + expected + "' but was '" + actual + "'");
    }

import java.io.File;

public class DeletedArtifact extends AbstractVerificationFailure {
    public DeletedArtifact(File file) {
        super(file);

    }

    @Override
    public void explainTo(TreeFormatter formatter) {
        formatter.append("artifact file has been deleted from local cache so verification cannot be performed");
    }

    public OnlyIgnoredKeys(File file) {
        super(file);
    }

    @Override
    public boolean isFatal() {
        return false;
    }

    @Override
    public void explainTo(TreeFormatter formatter) {
        formatter.append("artifact was signed but all keys were ignored");
    }

    public MissingSignature(File file) {
        super(file);
    }

    @Override
    public boolean isFatal() {
        return false;
    }

    @Override
    public void explainTo(TreeFormatter formatter) {
        formatter.append("artifact is not signed");
    }

import java.io.File;

public class MissingChecksums extends AbstractVerificationFailure {
    public MissingChecksums(File file) {
        super(file);
    }

    @Override
    public void explainTo(TreeFormatter formatter) {
        formatter.append("checksum is missing from verification metadata.");
    }

    File getFilePath();

    @Nullable
    default File getSignatureFile() {
        return null;
    }

    default boolean isFatal() {
        return true;
    }

    default void explainTo(TreeFormatter formatter) {

    }

    @Override
    public boolean isFatal() {
        return false;
    }

    @Override
    public File getSignatureFile() {
        return signatureFile;
    }

    @Override
    public void explainTo(TreeFormatter formatter) {
        formatter.append("artifact has signature file, but it contains no valid signatures");
    }

        if (inMultiErrors) {
            formatter.node("");
        }
        formatter.append("in repository '" + failure.getRepositoryName() + "': ");
        failure.getFailure().explainTo(formatter);
    }

    @Override
    public void reportAsMultipleErrors(Runnable action) {
        formatter.append("multiple problems reported:");
        formatter.startChildren();
        inMultiErrors = true;

    @Override
    public File getSignatureFile() {
        return signatureFile;
    }

    public Map<String, SignatureError> getErrors() {
        return errors;
    }

    @Override
    public void explainTo(TreeFormatter formatter) {
        if (errors.size() == 1) {
            Map.Entry<String, SignatureError> entry = errors.entrySet().iterator().next();
            formatter.append(toMessage(entry.getKey(), entry.getValue()));

        then:
        !ability.isBuildable()
    }

    def "explains reason when tool search is not successful" () {
        def visitor = Mock(DiagnosticsVisitor)

        when:
        result.isAvailable() >> false
        result.explain(_) >> { DiagnosticsVisitor v ->
            v.node("Tool search failed")
        }
        ability.explain(visitor)

        then:
        1 * visitor.node("Tool search failed")