Moq

This library provides macro that provides mock struct generating that implements trait.

[dependencies]
moq = "0.4"

Usage example

#[moq::automock]
trait Trait {
    fn func(&self, arg: i64) -> String;
}

#[test]
fn test_ok() {
    let mock = TraitMock::new()
        .expect_func(|arg: i64| {
            assert_eq!(arg, 42);
            format!("Hello, {}", arg)
        })
        .expect_func(|arg: i64| {
            assert_eq!(arg, -1);
            format!("Hello again, {}", -1)
        });
    
    mock.func(42);
    mock.func(-1);
}

#[test]
fn test_failed_extra_call() {
    let mock = TraitMock::new()
        .expect_func(|arg: i64| {
            assert_eq!(arg, 42);
            format!("Hello, {}", arg)
        });

    mock.func(42);
    mock.func(-1); // Panic here
}

#[test]
fn test_failed_missing_call() {
    let mock = TraitMock::new()
        .expect_func(|arg: i64| {
            assert_eq!(arg, 42);
            format!("Hello, {}", arg)
        })
        .expect_func(|arg: i64| {
            assert_eq!(arg, -1);
            format!("Hello again, {}", -1)
        });

    mock.func(42);
    // Panic here
}

async_trait also works, but the main limitation is to specify the automock macro above the async_trait

#[moq::automock]
#[async_trait::async_trait]
trait Trait {
    async fn func(&self, arg: i64) -> String;
}

#[tokio::test]
async fn test_ok() {
    let mock = TraitMock::new()
        .expect_func(|arg: i64| async {
            assert_eq!(arg, 42);
            format!("Hello, {}", arg)
        });
    
    mock.func(42).await;
}

You can find more examples in the tests.

TODO

• Supporting generic functions
• Supporting static functions
• Macro moq::mock!(..) for generating mock struct for external trait
• Generating mock struct for struct without trait
• Capturing environment in moq::lambda!

License