PersistedToolchains jdksExtra = read(jdksExtraIS);
            assertEquals(2, jdks.getToolchains().size());

            merger.merge(jdks, jdksExtra, TrackableBase.USER_LEVEL);
            assertEquals(4, jdks.getToolchains().size());
            assertEquals(2, jdksExtra.getToolchains().size());
        }
        try (InputStream jdksIS = MavenToolchainMergerTest.class.getResourceAsStream("toolchains-jdks.xml");

        assertEquals(1, result.getEffectiveToolchains().getToolchains().size());
        assertEquals(
                "TYPE", result.getEffectiveToolchains().getToolchains().get(0).getType());
        assertEquals(
                "user_value",
                result.getEffectiveToolchains()
                        .getToolchains()
                        .get(0)
                        .getProvides()

        MavenExecutionRequest executionRequest = new DefaultMavenExecutionRequest();
        when(session.getRequest()).thenReturn(executionRequest);

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

        assertEquals(0, toolchains.size());
    }

    @Test
    void testModelNoFactory() {
        MavenSession session = mock(MavenSession.class);

    }

    @Override
    public List<Toolchain> getToolchains(Session session, String type, Map<String, String> requirements)
            throws ToolchainManagerException {
        MavenSession s = InternalMavenSession.from(session).getMavenSession();
        List<org.apache.maven.toolchain.Toolchain> toolchains =
                toolchainManagerPrivate.getToolchains(s, type, requirements);

                return toolchains.get(0);
            }
        }

        return null;
    }

    @Override
    public List<Toolchain> getToolchains(MavenSession session, String type, Map<String, String> requirements) {
        List<ToolchainModel> models = session.getRequest().getToolchains().get(type);

        return selectToolchains(models, type, requirements);
    }

    private List<Toolchain> selectToolchains(

        super(target);
    }

    @Override
    protected Collection<AvailableToolChains.ToolChainCandidate> getPartialVersions() {
        List<AvailableToolChains.ToolChainCandidate> toolChains = AvailableToolChains.getToolChains();
        Map<AvailableToolChains.ToolFamily, AvailableToolChains.ToolChainCandidate> availableByFamily = Maps.newEnumMap(AvailableToolChains.ToolFamily.class);

     * @param type
     * @param requirements
     * @return the selected {@link Toolchain}s
     * @throws ToolchainManagerException if an exception occurs
     */
    @Nonnull
    List<Toolchain> getToolchains(@Nonnull Session session, String type, Map<String, String> requirements);

    /**
     *
     * @param session
     * @param type
     * @return the selected {@link Toolchain}

        } else {
            List<ToolchainModel> availableToolchains =
                    org.apache.maven.toolchain.model.ToolchainModel.toolchainModelToApiV4(
                            session.getRequest().getToolchains().get(type));

            if (availableToolchains != null) {
                for (ToolchainModel toolchainModel : availableToolchains) {
                    org.apache.maven.toolchain.model.ToolchainModel tm =

     * @param requirements the requirements, may be {@code null}
     * @return the matching toolchains, never {@code null}
     * @since 3.3.0
     */
    List<Toolchain> getToolchains(MavenSession session, String type, Map<String, String> requirements);

        project.modelRegistry.realize(path, type)
    }

    ModelMap<BinarySpec> getBinaries() {
        realizeModelElement("binaries", modelMap(BinarySpec))
    }

    NativeToolChainRegistry getToolChains() {
        realizeModelElement("toolChains", NativeToolChainRegistry)
    }

    PlatformContainer getPlatforms() {
        realizeModelElement("platforms", PlatformContainer)
    }