assert_called

assert_called(n) checks that a subscriber's handler ran exactly n times, counting a batch as one call.

n is the number of handler calls. A single-message handler is called once per delivery, and once more for each redelivery. A batch handler is called once per batch, so here n counts batches; assert_batch_sizes shows how big each one was. A publish through the harness runs to completion before it returns, so three publishes make three calls. On failure it panics with the number of calls it found. assert_called_once is the same check for one call, and outcomes shows how each call settled. A destination's assert_called(n) counts publishes instead.

Example

Macros

examples/testing_subscriber_calls.rs

#[tokio::test]
async fn the_handler_ran_once_per_order() -> Result<(), Box<dyn Error>> {
    let tb = TestApp::start(app()).await?;
    let broker = tb.broker::<MemoryBroker>();
    for id in 1..=3 {
        broker.message(&Order { id }).to("orders").publish().await?;
    }

    broker.subscriber("orders").assert_called(3);
    Ok(())
}

Manual

examples/manual/testing_subscriber_calls.rs

#[tokio::test]
async fn the_handler_ran_once_per_order() -> Result<(), Box<dyn Error>> {
    let tb = TestApp::start(app()).await?;
    let broker = tb.broker::<MemoryBroker>();
    for id in 1..=3 {
        broker.message(&Order { id }).to("orders").publish().await?;
    }

    broker.subscriber("orders").assert_called(3);
    Ok(())
}