Equity and Equity Options exchanges (NYSE, NASDAQ, CBOE, etc.) support a version of the FIX messaging standard for sending market quotes and orders. While the mechanics of creating, sending, and responding to FIX based requests and tracking their lifecycle are fairly straightforward, it tends to be fairly cumbersome to create test scenarios for simulating market behavior for testing trading strategies and systems against as the knowledge required often rests with traders and financial engineers, not software developers. This talk would present a DSL using the "Oslo" toolset that is capable of expressing order generation and responses from a range of market behaviors in terms of FIX messages in a dialect suitable for use by traders and financial engineers.