Session sessionv4 = mock(Session.class);
        when(session.getSession()).thenReturn(sessionv4);
        when(sessionv4.getToolchains()).thenReturn(toolchainModels);

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

        assertEquals(0, toolchains.size());

        @Nonnull
        @Override
        public List<org.apache.maven.api.Toolchain> getToolchains(
                @Nonnull Session session, @Nonnull String type, @Nullable Map<String, String> requirements)
                throws ToolchainManagerException {
            return getDelegate().getToolchains(session, type, requirements);
        }

        @Nonnull
        @Override

    Settings getSettings();

    /**
     * Retrieves toolchain models that have been explicitly configured.
     *
     * @return the toolchain models
     */
    @Nonnull
    Collection<ToolchainModel> getToolchains();

    /**
     * Retrieves the local repository associated with this session.
     *
     * @return the local repository instance
     */
    @Nonnull
    LocalRepository getLocalRepository();