Add a test for the UI API

[levitte]

Checklist

• tests are added or updated
• CLA is signed

Description of change

The best way to test the UI interface is currently by using an openssl
command that uses password_callback. The only one that does this is
'genrsa'.
Since password_callback uses a UI method derived from UI_OpenSSL(), it
ensures that one gets tested well enough as well.

[levitte]

I expect this test to fail on all MacOS X builds that aren't BUILDONLY.

[richsalz]

also to backport test to 1.1.0 if you want.

[levitte]

Yes, I do, just forgot to lable properly...

[levitte]

Actually, no... this wasn't a good enough test. I didn't notice that when password_callback notices a default password, it simply returns it instead of exercising UI... I can make sure to get a proper test in two ways:

1. Make it so password_callback goes through the motions with UI, even with a default password present.
2. Create test/uitest.c that does this.

Me, I'm tempted to go for the first option. It's our live code, might as well exercise it, ... and it's easier.

[levitte]

So I decided to change password_callback... as a side effect, it became a bit clearer what it does when.

[levitte]

@richsalz, this requires a re-approval on your part... or someone else in the team.

[levitte]

+0.3% coverage? Cool :-)

[levitte]

The Travis failures is exactly what I expected, and show that his test does what it's supposed to do.

[richsalz]

+1

[levitte]

Merged