Rex::Test via prove is broken with 1.5.0

Using something like:

REX_USER=user prove -v t/test.t

worked with 1.4.1, but it throws the following error with 1.5.0:

t/test.t .. 
Waiting for SSH to come up on 192.168.122.186:22.
[2017-04-12 11:56:16] ERROR - Error executing task:
[2017-04-12 11:56:16] ERROR - Can't call method "get_opts" on an undefined value at /home/ferki/perl5/perlbrew/perls/perl-5.24/lib/site_perl/5.24.1/Rex/Commands.pm line 1038.

Can't call method "get_opts" on an undefined value at /home/ferki/perl5/perlbrew/perls/perl-5.24/lib/site_perl/5.24.1/Rex/Commands.pm line 1038.
Dubious, test returned 29 (wstat 7424, 0x1d00)
No subtests run 

Test Summary Report
-------------------
t/test.t.t (Wstat: 7424 Tests: 0 Failed: 0)
  Non-zero exit status: 29
  Parse errors: No plan found in TAP output
Files=1, Tests=0, 16 wallclock secs ( 0.02 usr  0.01 sys +  1.62 cusr  1.28 csys =  2.93 CPU)
Result: FAIL

It might be easy to restore this, let's call "unofficial feature" (running rex tests with standard perl testing tools) :)

update: it seems it depends more on the type of tests running, than on the versoin of rex

Reproduce the failure with REX_USER=user prove -v t/test.t, then inspect Rex::Commands.pm around line 1038 and the Rex::Test test entry point. Compare the failing test types and the 1.4.1/1.5.0 behavior; done means the relevant Rex tests run through prove without the undefined get_opts error.