Add runtime tests

[J0WI]

Many images have custom runtime tests, would be great have some too.

[Llewellynvdm]

@J0WI are you still interested that we add this?

[J0WI]

@Llewellynvdm sure. Is there a way to install/check Joomla from CLI?

[Hackwar]

php installation/joomla.php

[Llewellynvdm]

Here is the PR that can also help shine some more light on this: joomla/joomla-cms#38325

Thanks @Hackwar

[J0WI]

That's only available in 4.3 but the Docker image is still on 4.2.

[Llewellynvdm]

Yes, we are holding back on J4.3 and will only push out 4.3.1 once its released.