basic type checking

the rlang type check standalone is probably overkill for this project, but some simple type checks should still be helpful.

R/syrup.R

@@ -33,6 +33,15 @@
 #' @export
 syrup <- function(expr, interval = .5, peak = FALSE, env = caller_env()) {
   expr <- substitute(expr)
+  if (!is_double(interval, n = 1, finite = TRUE)) {
+    abort("`interval` must be a single, finite numeric.")
+  }
+  if (!is_bool(peak)) {
+    abort("`peak` must be `TRUE` or `FALSE`.")
+  }
+  if (!is_environment(env)) {
+    abort("`env` must be an environment.")
+  }
 
   # create a new temporary R session `sesh`
   sesh <- callr::r_session$new()

tests/testthat/_snaps/syrup.md

@@ -1,3 +1,27 @@
+# syrup does basic type checks
+
+    Code
+      syrup(1, interval = "boop")
+    Condition
+      Error in `syrup()`:
+      ! `interval` must be a single, finite numeric.
+
+---
+
+    Code
+      syrup(1, peak = "no")
+    Condition
+      Error in `syrup()`:
+      ! `peak` must be `TRUE` or `FALSE`.
+
+---
+
+    Code
+      syrup(1, env = "schmenv")
+    Condition
+      Error in `syrup()`:
+      ! `env` must be an environment.
+
 # syrup warns with only one ID
 
     ! `expr` evaluated fully before syrup could take a snapshot of memory usage.

tests/testthat/test-syrup.R

@@ -58,6 +58,14 @@ test_that("syrup(interval) works", {
   expect_true(length(unique(res_01$id)) > length(unique(res_1$id)))
 })
 
+test_that("syrup does basic type checks", {
+  # the rlang type check standalone is probably overkill for this project,
+  # but some simple type checks should still be helpful.
+  expect_snapshot(error = TRUE, syrup(1, interval = "boop"))
+  expect_snapshot(error = TRUE, syrup(1, peak = "no"))
+  expect_snapshot(error = TRUE, syrup(1, env = "schmenv"))
+})
+
 test_that("syrup warns with only one ID", {
   expect_snapshot_warning(syrup(1))
 })