Add image_directory tests

These tests use the fwu_dut class to construct DUTs with
different firmware store configurations to check that the serialized
image directory correctly reflect the set of updatable components
supported by the DUT.

Signed-off-by: Julian Hall <julian.hall@arm.com>
Change-Id: I4a1d742a4942d22bb5ea747ad057c51f0d8f6643
3 files changed