test_that("register_selection_handler works", {
  res <- register_selection_handler("test")
  expect_type(res, "closure")
  expect_null(res(list()))
  processed <- res(list(a = "res"))
  expect_named(processed, "a")
  expect_type(processed, "character")
  expect_identical(attr(processed, "eventType"), "test")
  expect_identical(processed[["a"]], "res")
  shiny::removeInputHandler("g6R.test")
})