Language testing and second language acquisition research are both concerned with proficiency in the second language; given this shared interest, the rapprochement between these two domains may prove revealing and productive not only in terms of teaching practices, but also in taking a wide view of language, ranging across cognition, society and linguistics. The paper is focused on the conceptual notion of cognitive fluency as a fundamental indicator of students' oral production in a foreign language. Within the framework of this theoretical approach, it provides a critical appreciation of the performance-based speaking tests (in terms of their reliability in measuring fluency), devised within the Russian State TORFL system. It also reflects on the policy and practice of designing pedagogical materials for developing oral proficiency (cognitive fluency) in Russian learners at A1-B1 stages at LSE. Specific attention is paid to such key issues of the cognitive perspective as the transfer appropriate setting and flexibility of fluency related processing and thinking for speaking, which are seen to serve as important criteria both for effective testing, and in enhancing fluency.