Serial flasher Tests

##Overview

Two kinds of tests are written for serial flasher:

Qemu tests uses emulated esp32 to test correctness of the library.

Installation (Only for qemu tests)

Please refer to building qemu for instructions how to compile.

Before running qemu tests, qemu itself has to be launched first.

QEMU_PATH environment variable pointing to qemu-system-xtensa has to be defined.

export QEMU_PATH=path_to_qemu-system-xtensa
sh run_qemu.sh

Run qemu test

cmake .. -DQEMU_TEST=True && make && ./serial_flasher_test

Run host test

cmake .. -DQEMU_TEST=False && make && ./serial_flasher_test