Simply run:
# hidl_gen converts .hal to .h correctly
make hidl_gen_test
# converted .h can compile
make android.hardware.tests.expression@1.0
to run the tests.
b/30951879: int8_t is same as char, and when emitting output the
character corresponding to that number is emitted instead of
the number itself.
Change-Id: Icacba6b6262cc0026a94f64527b80e2c0e35e72e
