vertx / io.vertx.rxjava.ext.unit / TestContext / asyncAssertFailure

# asyncAssertFailure

`open fun <T : Any> asyncAssertFailure(): Handler<AsyncResult<T>>`

Creates and returns a new async handler, the returned handler controls the completion of the test. When the returned handler is called back with a failed result it completes the async operation. When the returned handler is called back with a succeeded result it fails the test.

Return
the async result handler

`open fun <T : Any> asyncAssertFailure(causeHandler: Handler<Throwable>): Handler<AsyncResult<T>>`

Creates and returns a new async handler, the returned handler controls the completion of the test. When the returned handler is called back with a failed result it completes the async operation. When the returned handler is called back with a succeeded result it fails the test.

### Parameters

`causeHandler` - the cause handler

Return
the async result handler