assert_called_once

assert_called_once checks that exactly one message was published to the destination.

The assertion counts the messages in the record, published::<T>(name), not the handler calls that produced them. It panics with the count it found when the record holds none or more than one. It returns the record, so with, with_raw and with_header chain after it. assert_called(n) checks any other count, and assert_not_called checks that nothing was published.

Example

Macros

examples/testing_published.rs

#[tokio::test]
async fn one_order_gets_one_receipt() -> Result<(), Box<dyn Error>> {
    let tb = TestApp::start(app()).await?;
    let broker = tb.broker::<MemoryBroker>();
    broker
        .message(&Order { id: 7, seats: 2 })
        .to("orders")
        .publish()
        .await?;

    broker.published::<Receipt>("receipts").assert_called_once();
    Ok(())
}

Manual

examples/manual/testing_published.rs

#[tokio::test]
async fn one_order_gets_one_receipt() -> Result<(), Box<dyn Error>> {
    let tb = TestApp::start(app()).await?;
    let broker = tb.broker::<MemoryBroker>();
    broker
        .message(&Order { id: 7, seats: 2 })
        .to("orders")
        .publish()
        .await?;

    broker.published::<Receipt>("receipts").assert_called_once();
    Ok(())
}