Paper is focused on problems of acceptance tests automation in behavior driven development (BDD). We illustrate basic ideas of BDD by some development and testing examples. Special attention is being paid to difficulties of converting customer-side test stories into executable unit tests. We analyze process of marking up of test stories by a QA engineer for their subsequent automated conversion into the corresponding test classes and test methods. We define tasks for developing further tools aimed to support acceptance tests automation and to improve BDD based test story language.