test-bot: Install dependencies for Cask container tests.

[reitermarkus]

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In preparation of #725,

• adobe-air
• cabextract
• unar and
• xz

have to be installed before running brew cask-tests, otherwise some of the container tests will be skipped.

[MikeMcQuaid]

have to be installed before running brew cask-tests, otherwise some of the container tests will be skipped.

Longer-term we need to figure out a way of testing these things that doesn't require additional dependencies being installed on our bots (like brew tests does). Eventually we'll want to merge brew tests and brew cask-tests too.

Unfortunately the brew install does an implicit tap of homebrew/core which will be relatively slow. Where are the casks stored in this case? It's not testing a /usr/local Homebrew install.

[reitermarkus]

Longer-term we need to figure out a way of testing these things that doesn't require additional dependencies

I completely agree, however, I don't see a way to test the correct detection and extraction of containers without having the tools to extract them installed. I think we can neglect at least cabextract and xz for now, as there aren't any Casks using them. Also only one using unar will be left after Homebrew/homebrew-cask#23918 is merge.

[MikeMcQuaid]

I completely agree, however, I don't see a way to test the correct detection and extraction of containers without having the tools to extract them installed. I think we can neglect at least cabextract and xz for now, as there aren't any Casks using them.

Sounds like a good argument to 💀 that code 😉.

[MikeMcQuaid]

Would it be enough to have these installed systemwide on the build machines? This means they would likely not be kept particularly up-to-date but might be nicer than sticking them here.

[reitermarkus]

If that's possible, yes, as long as they can extract the containers I don't care if they are up-to-date.

[MikeMcQuaid]

Passing on this because I'd like to get brew cask-tests so it doesn't require caskroom to be tapped and this is going in the opposite direction.