testAsync
The test()
function is the value imported from the test
module. Each invocation of this function results in reporting the test to the TestsStream
.
The TestContext
object passed to the fn
argument can be used to perform actions related to the current test. Examples include skipping the test, adding additional diagnostic information, or creating subtests.
test()
returns a Promise
that fulfills once the test completes. if test()
is called within a suite, it fulfills immediately. The return value can usually be discarded for top level tests. However, the return value from subtests should be used to prevent the parent test from finishing first and cancelling the subtest as shown in the following example.
test('top level test', async (t) => {
// The setTimeout() in the following subtest would cause it to outlive its
// parent test if 'await' is removed on the next line. Once the parent test
// completes, it will cancel any outstanding subtests.
await t.test('longer running subtest', async (t) => {
return new Promise((resolve, reject) => {
setTimeout(resolve, 1000);
});
});
});
The timeout
option can be used to fail the test if it takes longer than timeout
milliseconds to complete. However, it is not a reliable mechanism for canceling tests because a running test might block the application thread and thus prevent the scheduled cancellation.
Since
v18.0.0, v16.17.0
Return
Fulfilled with undefined
once the test completes, or immediately if the test runs within a suite.
Parameters
The name of the test, which is displayed when reporting test results. Defaults to the name
property of fn
, or '<anonymous>'
if fn
does not have a name.
Configuration options for the test.
The function under test. The first argument to this function is a {@link TestContext} object. If the test uses callbacks, the callback function is passed as the second argument.