For data allocated and maintained by QByteArray, there's a guarantee
that data() is null-terminated. This holds true even for null and empty,
where logically the terminating character should never be dereferenced.
For tests that modify or generate QByteArrays, this ensures the
invariant is kept.
In the toFromHex() text, const-ness of temporary variables was dropped
to enable the test macro to be used, as the qualification didn't add
much to the test otherwise.
Change-Id: I7ee52e79e3a9df7de18c743f3698dab688e6bf0e
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@nokia.com>