zulip/frontend_tests/node_tests/settings_data.js

const settings_data = zrequire('settings_data');
const settings_config = zrequire('settings_config');

set_global('page_params', {});

/*
    Some methods in settings_data are fairly
    trivial, so the meaningful tests happen
    at the higher layers, such as when we
    test people.js.
*/

const isaac = {
    email: 'isaac@example.com',
    delivery_email: 'isaac-delivery@example.com',
};

run_test('email_for_user_settings', () => {
    const email = settings_data.email_for_user_settings;

    page_params.realm_email_address_visibility = settings_config.email_address_visibility_values
        .admins_only.code;
    assert.equal(email(isaac), undefined);

    page_params.is_admin = true;
    assert.equal(email(isaac), isaac.delivery_email);

    page_params.realm_email_address_visibility = settings_config.email_address_visibility_values
        .nobody.code;
    assert.equal(email(isaac), undefined);

    page_params.is_admin = false;
    assert.equal(email(isaac), undefined);

    page_params.realm_email_address_visibility = settings_config.email_address_visibility_values
        .everyone.code;
    assert.equal(email(isaac), isaac.email);
});