Expand tests

[mpadge]

Several recent PRs have modified output text, yet this had no effect on tests. These include:

• Add to admonishment against import(<pkg>) usage #170
• rm 'dangerous_fn_linter' to fix #173 #177

Plus new aspects that need to be tested:

• Add package_hooks_linter #178

And the following which now rely on default lintr messages, rather than hard-coded ones here, and which may or may not have changed?

• semicolon linter for #171 #175
• rm internal 'seq_linter' for lintr version to fix #172 #176

Tests should obviously cover these explicit strings, yet clearly do not in current form. Ping @MichaelChirico

[MichaelChirico]

Tests should obviously cover these explicit strings

I'm not sure that makes sense, those strings are pretty fragile. See here for the type of clunky workaround I've had to set up for this type of test in the past:

https://github.com/Rdatatable/data.table/blob/e22f7742aee78651fe09aed1434625947dda600a/inst/tests/tests.Rraw#L150-L160

I would recommend testing against something more stable, e.g. as.data.frame(x)$linter or x[[1L]]$linter.

There are some cases (like paste_linter()) where several rules are under the same $linter where you'd have to check some parts of the $message too, in which case I'd try and use a minimal regex instead of capturing the exact string.