Micro execution is the ability to execute any code fragment without a user-provided test driver or input data. The user simply identifies a function or code location in an exe or dll. A runtime Virtual Machine (VM) customized for testing purposes then starts executing the code at that location, catches all memory operations before they occur, allocates memory on-the-fly in order to perform those read/write memory operations, and provides input values according to a customizable memory policy, which defines what read memory accesses should be treated as inputs.