test against sf classes

[dcooley]

I think you can stick

remotes::install_github("r-spatial/sf")

Before or after this (I forget which is more likely to work): https://github.com/dcooley/sfheaders/blob/master/.github/workflows/R-CMD-check.yaml#L68 ...in a copy of your R-CMD-check.yaml file.

If you're going return an object of class sf or sfc_*, you should probably expect_identical() your output with that of sf...they're sf's objects.

If there is an in-memory structure that's faster to create (from a data frame or otherwise), you could give it another class ("sfheaders"?) and implement st_as_sfc()/st_as_sf() using sf's constructors. You can dynamically register those methods to avoid requiring sf in Imports (see here: https://github.com/paleolimbot/geovctrs/blob/master/R/zzz.R#L21 ).

Originally posted by @paleolimbot in #49 (comment)