Path path = Paths.get("").toAbsolutePath();

        MavenSession mavenSession = createMavenSession(null);
        mavenSession.getRequest().setTopDirectory(path);
        mavenSession.getRequest().setRootDirectory(path);

        Object result = new PluginParameterExpressionEvaluator(mavenSession, new MojoExecution(null))
                .evaluate("${session.rootDirectory.uri}");
        assertEquals(path.toUri(), result);

        MavenSession mavenSession = createSession(container, repo, executionProperties);
        mavenSession.setCurrentProject(project);
        mavenSession.getRequest().setRootDirectory(rootDirectory);
        mavenSession.getRequest().setTopDirectory(rootDirectory);

        DefaultSession session = new DefaultSession(

        InternalMavenSession.from(InternalSession.from(buildingRequest.getRepositorySession()))
                .getMavenSession()
                .getRequest()
                .setRootDirectory(projectRoot);

        try (InputStream pomResource =
                DefaultMavenProjectBuilderTest.class.getResourceAsStream("/projects/reread/pom1.xml")) {

        FileUtils.copyDirectoryStructure(new File("src/test/resources/projects/grandchild-check"), tempDir.toFile());

        MavenSession mavenSession = createMavenSession(null);
        mavenSession.getRequest().setRootDirectory(tempDir);
        ProjectBuildingRequest configuration = new DefaultProjectBuildingRequest();
        configuration.setRepositorySession(mavenSession.getRepositorySession());

     * @since 3.3.0
     */
    Map<String, List<ToolchainModel>> getToolchains();

    /**
     * @since 3.3.0
     * @deprecated use {@link #setRootDirectory(Path)} instead
     */
    @Deprecated
    void setMultiModuleProjectDirectory(File file);

    /**
     * @since 3.3.0
     * @deprecated use {@link #getRootDirectory()} instead
     */

    }

    protected MavenExecutionRequest createMavenExecutionRequest(File pom) throws Exception {
        MavenExecutionRequest request = new DefaultMavenExecutionRequest()
                .setRootDirectory(pom != null ? pom.toPath().getParent() : null)
                .setPom(pom)
                .setProjectPresent(true)
                .setShowErrors(true)

            // maven requires this to be set; so default it (and see below at POM)
            request.setMultiModuleProjectDirectory(
                    context.invokerRequest.topDirectory().toFile());
            request.setRootDirectory(context.invokerRequest.topDirectory());
        }

        request.setToolchains(
                Optional.ofNullable(context.effectiveToolchains).map(PersistedToolchains::getToolchains).stream()

            throw new IllegalStateException(RootLocator.UNABLE_TO_FIND_ROOT_PROJECT_MESSAGE);
        }
        return rootDirectory;
    }

    @Override
    public MavenExecutionRequest setRootDirectory(Path rootDirectory) {
        this.rootDirectory = rootDirectory;
        return this;
    }

    @Override
    public Path getTopDirectory() {
        return topDirectory;
    }

        if (context.invokerRequest.rootDirectory().isPresent()) {
            request.setMultiModuleProjectDirectory(
                    context.invokerRequest.rootDirectory().get().toFile());
            request.setRootDirectory(context.invokerRequest.rootDirectory().get());
        }

        request.addPluginGroup("org.apache.maven.plugins");
        request.addPluginGroup("org.codehaus.mojo");
    }

    /**