Add REQUIRES postgres to tests/utils/installation.shtest test

[aemerson]

If postgresql isn't installed on the test machine this test fails
during the attempt to build the psycopg2 package with error:
Error: pg_config executable not found.

[ldionne]

I think this makes sense for now, but in fact I was thinking about requiring postgres in order to run the tests. That way we'd always ensure that we run all the tests. Do you have an opinion about that?

[aemerson]

I think this makes sense for now, but in fact I was thinking about requiring postgres in order to run the tests. That way we'd always ensure that we run all the tests. Do you have an opinion about that?

I don't have a strong opinion, but postgresql is quite a heavy dependency when lnt uses sqlite by default isn't it? There's also a binary package that I tested fixes this issue too, psycopg2-binary but it's only suggested for dev/testing and not for production. Maybe we could somehow use that for tests.

[ldionne]

I think this makes sense for now, but in fact I was thinking about requiring postgres in order to run the tests. That way we'd always ensure that we run all the tests. Do you have an opinion about that?

I don't have a strong opinion, but postgresql is quite a heavy dependency when lnt uses sqlite by default isn't it? There's also a binary package that I tested fixes this issue too, psycopg2-binary but it's only suggested for dev/testing and not for production. Maybe we could somehow use that for tests.

I ended up not requiring postgres all the time, but instead detecting whether it's installed and automatically enabling the tests in that case. And we now have coverage with Github actions that have (and don't have) Postgres installed.