assertEquals(
                RootLocator.UNABLE_TO_FIND_ROOT_PROJECT_MESSAGE,
                assertThrows(IllegalStateException.class, session::getRootDirectory)
                        .getMessage());
    }

    @Test
    void testRootDirectory() {
        RepositorySystemSession rss = new DefaultRepositorySystemSession(h -> false);

     * containing the {@code .mvn} directory or flagged with {@code root="true"}.
     *
     * @throws IllegalStateException if the root directory could not be found
     * @see Session#getRootDirectory()
     */
    @Nonnull
    Path getRootDirectory();

    /**
     * Returns project parent project, if any.
     */
    @Nonnull
    Optional<Project> getParent();

    }

    @Override
    public boolean isRootProject() {
        return getBasedir().equals(getRootDirectory());
    }

    @Override
    public Path getRootDirectory() {
        return project.getRootDirectory();
    }

    @Override
    public Optional<Project> getParent() {
        MavenProject parent = project.getParent();

    @Override
    public Instant getStartTime() {
        return getMavenSession().getRequest().getStartTime().toInstant();
    }

    @Override
    public Path getRootDirectory() {
        return getMavenSession().getRequest().getRootDirectory();
    }

    @Override
    public Path getTopDirectory() {
        return getMavenSession().getRequest().getTopDirectory();
    }

    @Nonnull
    @Override

                }
            }

            private void doLoadFullReactor() {
                Path rootDirectory;
                try {
                    rootDirectory = request.getSession().getRootDirectory();
                } catch (IllegalStateException e) {
                    // if no root directory, bail out
                    return;
                }
                List<Path> toLoad = new ArrayList<>();