with_state

TestApp::with_state starts the app with a state the test builds in place of on_startup, wired to the brokers of the app.

It is for a state that reaches outside the service: a catalog, a database, a mail client the test cannot or should not call. The harness connects each broker in process first, then calls the builder, so the state's publishers pair against connected brokers. TestBrokers::broker::<B>() returns the connected form of the app's broker of type B. A publisher built from it publishes onto the bus the assertions read, such as published::<T>(name) and its with. The app's on_startup does not run; after_startup and everything else of startup do, as in TestApp::start. TestBrokers::broker panics when the app has no broker of type B or more than one.

Example

Macros

examples/testing_starting.rs

#[tokio::test]
async fn an_order_is_quoted_from_the_catalog() -> Result<(), Box<dyn Error>> {
    let tb = TestApp::with_state(app(), |brokers| Pricing {
        catalog: Catalog {
            prices: HashMap::from([(7, 1250)]),
        },
        quotes: brokers.broker::<MemoryBroker>().publisher(),
    })
    .await?;
    tb.broker::<MemoryBroker>()
        .message(&Order { id: 7 })
        .publish()
        .await?;

    tb.broker::<MemoryBroker>()
        .published::<Quote>("quotes")
        .assert_called_once()
        .with(&Quote {
            order_id: 7,
            cents: 1250,
        });
    Ok(())
}

Manual

examples/manual/testing_starting.rs

#[tokio::test]
async fn an_order_is_quoted_from_the_catalog() -> Result<(), Box<dyn Error>> {
    let tb = TestApp::with_state(app(), |brokers| Pricing {
        catalog: Catalog {
            prices: HashMap::from([(7, 1250)]),
        },
        quotes: brokers.broker::<MemoryBroker>().publisher(),
    })
    .await?;
    tb.broker::<MemoryBroker>()
        .message(&Order { id: 7 })
        .publish()
        .await?;

    tb.broker::<MemoryBroker>()
        .published::<Quote>("quotes")
        .assert_called_once()
        .with(&Quote {
            order_id: 7,
            cents: 1250,
        });
    Ok(())
}