toolchainModels.put("unknown", Collections.singletonList(new ToolchainModel()));
        executionRequest.setToolchains(toolchainModels);
        when(session.getRequest()).thenReturn(executionRequest);

        List<Toolchain> toolchains = toolchainManager.getToolchains(session, "unknown", null);

        assertEquals(0, toolchains.size());

     */
    @Nonnull
    String getSource();

    /**
     * Gets the one-based index of the line containing the problem. The line number should refer to some text file that
     * is given by {@link #getSource()}.
     *
     * @return the one-based index of the line containing the problem or a non-positive value if unknown
     */
    int getLineNumber();

     * @param message The detail message of the problem, may be {@code null}.
     * @param line The one-based index of the line containing the problem or {@code -1} if unknown.
     * @param column The one-based index of the column containing the problem or {@code -1} if unknown.
     * @param cause The cause of the problem, may be {@code null}.
     */
    void add(Problem.Severity severity, String message, int line, int column, Exception cause);

        // execute
        ToolchainPrivate[] toolchains = toolchainManager.getToolchainsForType("unknown", session);

        // verify
        verify(logger).error("Missing toolchain factory for type: unknown. Possibly caused by misconfigured project.");
        assertEquals(0, toolchains.length);
    }

    @Test

     * @return the type
     */
    @Nonnull
    @Override
    default Type require(@Nonnull String id) {
        return lookup(id).orElseThrow(() -> new IllegalArgumentException("Unknown extensible enum value '" + id + "'"));
    }

 *
 * @since 3.0.2
 */
public interface RuntimeInformation {

    /**
     * Retrieves the current Maven version, for example "3.0.2".
     *
     * @return The current Maven version or an empty string if unknown, never {@code null}.
     */
    String getMavenVersion();

    /**
     * Checks whether the current Maven runtime matches the specified version range. A version range can either use the

 *
 */
public interface MetadataReader {

    /**
     * The key for the option to enable strict parsing. This option is of type {@link Boolean} and defaults to {@code
     * true}. If {@code false}, unknown elements will be ignored instead of causing a failure.
     */
    String IS_STRICT = "org.apache.maven.artifact.repository.metadata.io.isStrict";

    /**
     * Reads the metadata from the specified file.
     *

    void setProfiles(List<Profile> profiles);

    List<Profile> getProfiles();

    /**
     * Gets the start time of the build.
     *
     * @return The start time of the build or {@code null} if unknown.
     */
    Date getBuildStartTime();

    /**
     * Sets the start time of the build.
     *
     * @param buildStartTime The start time of the build, may be {@code null}.
     */

                }
            }
            stringBuilder.append(" @ line ").append(inputLocation.getLineNumber());
            return stringBuilder.toString();
        } else {
            return "unknown";
        }
    }

    private String mojoInfo(MojoDescriptor mojoDescriptor, Class<?> mojoClass) {
        return mojoDescriptor.getFullGoalName() + " (" + mojoClass.getName() + ")";
    }

        return new StringBuilder(128)
            .append((getGroupId() == null) ? "[unknown-group-id]" : getGroupId())
            .append(":")
            .append((getArtifactId() == null) ? "[unknown-artifact-id]" : getArtifactId())
            .append(":")
            .append((getVersion() == null) ? "[unknown-version]" : getVersion())
            .toString();
    }

    /**