Expect at least one element to match

pz_expect_exists() passes when at least one element matching target is in the DOM, visible or not. It's the one expectation where multiple matches don't all have to satisfy the check: existence needs only one. With not = TRUE it passes when nothing matches.

Expectations retry until they pass or timeout elapses, then return ctx invisibly. Outside of testthat, a failure aborts with a classed error of class "paparazzi_expectation_failure" showing the target, the last observed value, and the time waited; inside testthat, the failure is instead reported as a test failure, and a pass counts as a successful testthat expectation.

Usage

pz_expect_exists(ctx, target = NULL, ..., not = FALSE, timeout = NULL)

Arguments

ctx

A paparazzi context.

target

A CSS selector string, a pz_loc() spec, or a list of specs and strings (a union matching any of them). NULL means the current context: the pinned set at a scoped context (so pz_expect_exists() on one trivially passes while the scope is live), the page body at the root.

...

Checked empty; reserved for future use.

not

Invert the check.

timeout

Seconds to wait for the expectation to pass; NULL (default) uses the session default, 0 checks once.

Value

ctx, invisibly.

Examples

if (FALSE) { # paparazzi:::examples_run()
page <- pz_open(pz_example("tasks"))
page |> pz_expect_exists(target = ".task")

# The help panel is in the page even while it's hidden
page |> pz_expect_exists(target = "#help")
page |> pz_expect_exists(target = ".error-message", not = TRUE)

# A failing expectation retries until the timeout, then errors
try(pz_expect_exists(page, target = ".error-message", timeout = 0.5))
pz_close(page)
}