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#' Run a test
#'
#' @description
#' A test encapsulates a series of expectations about a small, self-contained
#' unit of functionality. Each test contains one or more expectations, such as
#' [expect_equal()] or [expect_error()], and lives in a `test/testhat/test*`
#' file, often together with other tests that relate to the same function or set
#' of functions.
#'
#' Each test has its own execution environment, so an object created in a test
#' also dies with the test. Note that this cleanup does not happen automatically
#' for other aspects of global state, such as session options or filesystem
#' changes. Avoid changing global state, when possible, and reverse any changes
#' that you do make.
#'
#' @param desc Test name. Names should be brief, but evocative. It's common to
#' write the description so that it reads like a natural sentence, e.g.
#' `test_that("multiplication works", { ... })`.
#' @param code Test code containing expectations. Braces (`{}`) should always
#' be used in order to get accurate location data for test failures.
#' @return When run interactively, returns `invisible(TRUE)` if all tests
#' pass, otherwise throws an error.
#' @export
#' @examples
#' test_that("trigonometric functions match identities", {
#' expect_equal(sin(pi / 4), 1 / sqrt(2))
#' expect_equal(cos(pi / 4), 1 / sqrt(2))
#' expect_equal(tan(pi / 4), 1)
#' })
#'
#' \dontrun{
#' test_that("trigonometric functions match identities", {
#' expect_equal(sin(pi / 4), 1)
#' })
#' }
test_that <- function(desc, code) {
check_string(desc)
code <- substitute(code)
if (edition_get() >= 3) {
if (!is_call(code, "{")) {
warn(
"The `code` argument to `test_that()` must be a braced expression to get accurate file-line information for failures.",
class = "testthat_braces_warning"
)
}
}
# Must initialise interactive reporter before local_test_context()
reporter <- get_reporter() %||% local_interactive_reporter()
local_test_context()
test_code(
desc,
code,
env = parent.frame(),
reporter = reporter
)
}
# Access error fields with `[[` rather than `$` because the
# `$.Throwable` from the rJava package throws with unknown fields
test_code <- function(test, code, env, reporter, skip_on_empty = TRUE) {
frame <- caller_env()
if (!is.null(test)) {
reporter$start_test(context = reporter$.context, test = test)
on.exit(reporter$end_test(context = reporter$.context, test = test))
}
ok <- TRUE
# @param debug_end How many frames should be skipped to find the
# last relevant frame call. Only useful for the DebugReporter.
register_expectation <- function(e, debug_end) {
srcref <- e[["srcref"]] %||% find_expectation_srcref(frame)
e <- as.expectation(e, srcref = srcref)
# Data for the DebugReporter
if (debug_end >= 0) {
start <- eval_bare(quote(base::sys.nframe()), test_env) + 1L
e$start_frame <- start
e$end_frame <- sys.nframe() - debug_end - 1L
}
e$test <- test %||% "(code run outside of `test_that()`)"
ok <<- ok && expectation_ok(e)
reporter$add_result(context = reporter$.context, test = test, result = e)
}
# Any error will be assigned to this variable first
# In case of stack overflow, no further processing (not even a call to
# signalCondition() ) might be possible
test_error <- NULL
expressions_opt <- getOption("expressions")
expressions_opt_new <- min(expressions_opt + 500L, 500000L)
# If no handlers are called we skip: BDD (`describe()`) tests are often
# nested and the top level might not contain any expectations, so we need
# some way to disable
handled <- !skip_on_empty
handle_error <- function(e) {
handled <<- TRUE
# First thing: Collect test error
test_error <<- e
# Increase option(expressions) to handle errors here if possible, even in
# case of a stack overflow. This is important for the DebugReporter.
# Call options() manually, avoid withr overhead.
options(expressions = expressions_opt_new)
on.exit(options(expressions = expressions_opt), add = TRUE)
# Add structured backtrace to the expectation
if (can_entrace(e)) {
e <- cnd_entrace(e)
}
test_error <<- e
# Error will be handled by handle_fatal() if this fails; need to do it here
# to be able to debug with the DebugReporter
register_expectation(e, 2)
e[["handled"]] <- TRUE
test_error <<- e
}
handle_fatal <- function(e) {
handled <<- TRUE
# Error caught in handle_error() has precedence
if (!is.null(test_error)) {
e <- test_error
if (isTRUE(e[["handled"]])) {
return()
}
}
register_expectation(e, 0)
}
handle_expectation <- function(e) {
handled <<- TRUE
register_expectation(e, 6)
invokeRestart("continue_test")
}
handle_warning <- function(e) {
# When options(warn) < 0, warnings are expected to be ignored.
if (getOption("warn") < 0) {
return()
}
# When options(warn) >= 2, warnings are converted to errors.
# So, do not handle it here so that it will be handled by handle_error.
if (getOption("warn") >= 2) {
return()
}
if (!inherits(e, "testthat_warn")) {
e <- cnd_entrace(e)
}
register_expectation(e, 5)
maybe_restart("muffleWarning")
}
handle_message <- function(e) {
if (edition_get() < 3) {
maybe_restart("muffleMessage")
}
}
handle_skip <- function(e) {
handled <<- TRUE
debug_end <- if (inherits(e, "skip_empty")) -1 else 2
register_expectation(e, debug_end)
signalCondition(e)
}
test_env <- new.env(parent = env)
old <- options(rlang_trace_top_env = test_env)[[1]]
on.exit(options(rlang_trace_top_env = old), add = TRUE)
withr::local_options(testthat_topenv = test_env)
before <- inspect_state()
tryCatch(
withCallingHandlers(
{
eval(code, test_env)
if (!handled && !is.null(test)) {
skip_empty()
}
},
expectation = handle_expectation,
skip = handle_skip,
warning = handle_warning,
message = handle_message,
error = handle_error
),
# some errors may need handling here, e.g., stack overflow
error = handle_fatal,
# skip silently terminate code
skip = function(e) {}
)
after <- inspect_state()
if (!is.null(test)) {
cnd <- testthat_state_condition(before, after, call = sys.call(-1))
if (!is.null(cnd)) {
register_expectation(cnd, 0)
}
}
invisible(ok)
}
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