How to use memdb_frame() in an R package test

Question

I've added a function to a package that performs a simple operation on a dbplyr database connection. In interactive testing, I create a dummy database with memdb_frame like this:

x <- memdb_frame(caseID = 1, DOB = 2, Other = 3)

And then the function performs its job on x. But when I try to create a database the same way in the package's testthat tests, I get an error:

 Error in `(function (cond) 
.Internal(C_tryCatchHelper(addr, 1L, cond)))(structure(list(message = "there is no package called 'RSQLite'", 
    call = loadNamespace(x), package = "RSQLite", lib.loc = NULL), class = c("packageNotFoundError", 
"error", "condition")))`: error in evaluating the argument 'drv' in selecting a method for function 'dbConnect': there is no package called 'RSQLite'

I think earlier in debugging, it was giving an error like this for RMySQL, which I might have fixed by adding RMySQL to the package's Suggests list.

My Suggests list is currently:

Suggests:
    dbplyr,
    knitr,
    rmarkdown,
    RMySQL,
    sf,
    testthat (>= 3.0.0),
    tibble,
    tidygraph

And traceback includes:

  2. │ ├─dplyr::copy_to(src_memdb(), tibble(...), name = .name)
  3. │ └─dbplyr::src_memdb()
  4. │   ├─dbplyr:::cache_computation(...)
  5. │   │ └─base::force(computation)
  6. │   ├─dbplyr::src_dbi(...)
  7. │   │ └─base::force(con)
  8. │   └─DBI::dbConnect(RSQLite::SQLite(), ":memory:", create = TRUE)

Answer 1

Edit the package's DESCRIPTION file to include RMySQL in Suggests. Then the above test runs correctly. Including RSQLite is not necessary.