tests: Make the build reproductible

[bigon]

Fixes: #106

[bigon]

@hughsie I was thinking about something like that

[hughsie]

So that indeed makes it reproducible, but also disables the self tests..

[bigon]

@hughsie OK my new patch is better, and the tests are passing

[hughsie]

@superm1 -- I know this is nothing to do with you, but could you review as I guess we'll have to do the same workaround for fwupd and our other projects.

[superm1]

@bigon would you mind doing the same kind of PR to fwupd too? I know Debian has had a reproducible builds failure there for a while and it's most likely this exact same problem.

[bigon]

@superm1 I can have a look later

[hughsie]

I can have a look later

I think libxmlb is probably affected like this too.

[bigon]

@hughsie Weird, both fwupd and libxmlb are fine

But indeed looking at the code, they use the same method 🤔

[superm1]

@hughsie Weird, both fwupd and libxmlb are fine

But indeed looking at the code, they use the same method 🤔

That's super bizarre. I definitely saw failures in buster I remember. I think submit the changes anyway. They do make sense for reproducible builds to keep working.