inject helper message into postgres default check for each test run w…

…ith db connection fxn

tests/testthat/helper-rls.R

@@ -1,11 +1,21 @@
+postgres_default <- function(...) {
+  tryCatch({
+    # replaces RPostgres:::connect_default
+    DBI::dbConnect(RPostgres::Postgres(), ...)
+  }, error = function(...) {
+    vars <- "try setting env vars: PGHOST, PGPORT, PGUSER, PGDATABASE"
+    testthat::skip(glue("Test database not available. {vars}"))
+  })
+}
+
 #' Execute an R expression with access to a database connection.
 #'
-#' @details Copied from the RPostgres package, thank you!
+#' @details Copied unchanged from the RPostgres package, thank you!
 #' @param expr (expression) Any R expression.
 #' @param con (PqConnection) A database connection, by default.
 #' [dbConnect(RPostgres::Postgres())].
 #' @return the return value of the evaluated `expr`
-with_database_connection <- function(expr, con = RPostgres::postgresDefault()) {
+with_database_connection <- function(expr, con = postgres_default()) {
   context <- list2env(list(con = con), parent = parent.frame())
   eval(substitute(expr), envir = context)
 }