Skip tests with missing test vectors instead of failing.

[jhb]

Summary

This copes more gracefully when older version of the nist-kat package
are intalled that don't have newer test vectors such as CCM or plain
SHA.

If the nist-kat package is not installed at all, this still fails with
an error.

Test Plan

• ran updated cryptotest.py with CCM and plain SHA support against older nist-kat package and now get skips instead of failures.

[jhb]

I think this should go in before the CCM and plain SHA changes so that Jenkins doesn't blow up with new failures due to the updated nist-kat package not yet being available.

[cem]

LGTM. I'm assuming the message is printed and not silently discarded if tests are skipped when running on the command line? I don't want silent "success" when KAT vectors are missing.

[jhb]

By default you just get a 's' in output instead of '.' With '-v' you get the full message:

# python2.7 ./cryptotest.py
.s.s.s..s.s...
----------------------------------------------------------------------
Ran 14 tests in 5.735s

# python2.7 ./cryptotest.py -v
test_cbc (__main__.GendCryptoTestCase) ... ok
test_ccm (__main__.GendCryptoTestCase) ... skipped 'Missing ccmtestvectors test vectors'
test_gcm (__main__.GendCryptoTestCase) ... ok
test_sha (__main__.GendCryptoTestCase) ... skipped 'Missing shabytetestvectors test vectors'
test_sha1hmac (__main__.GendCryptoTestCase) ... ok
test_tdes (__main__.GendCryptoTestCase) ... skipped 'skipping DES on ccr0'
test_xts (__main__.GendCryptoTestCase) ... ok
test_cbc (__main__.GendCryptoTestCase) ... ok
test_ccm (__main__.GendCryptoTestCase) ... skipped 'Missing ccmtestvectors test vectors'
test_gcm (__main__.GendCryptoTestCase) ... ok
test_sha (__main__.GendCryptoTestCase) ... skipped 'Missing shabytetestvectors test vectors'
test_sha1hmac (__main__.GendCryptoTestCase) ... ok
test_tdes (__main__.GendCryptoTestCase) ... ok
test_xts (__main__.GendCryptoTestCase) ... ok

----------------------------------------------------------------------
Ran 14 tests in 5.699s

OK (skipped=5)

[cem]

In D20034#430600, @jhb wrote:

By default you just get a 's' in output instead of '.' With '-v' you get the full message:

Works for me, thanks.