getContentAPIAgent = async () => {
    try {
        const app = await startGhost();
        const originURL = configUtils.config.get('url');

        return new ContentAPITestAgent(app, {
            apiURL: '/ghost/api/content/',
            originURL
        });
    } catch (error) {
        error.message = `Unable to create test agent. ${error.message}`;
        throw error;
    }
}
Creates a ContentAPITestAgent which is a drop-in substitution for supertest.
It is automatically hooked up to the Content API so you can make requests to e.g.
agent.get('/posts/') without having to worry about URL paths
@returns {Promise<InstanceType<ContentAPITestAgent>>} agent