mockall 0.9.1

// vim: tw=80
//! mock a generic struct and instantiate it with a parameter type that does not
//! implement Default
#![deny(warnings)]

use mockall::*;

struct NonDefault();

trait Foo<T: 'static> {
    fn foo(&self) -> T;
}
mock! {
    ExternalStruct<T: 'static> {}
    impl<T: 'static> Foo<T> for ExternalStruct<T> {
        fn foo(&self) -> T;
    }
}

#[test]
#[should_panic(expected =
    "MockExternalStruct::foo: Expectation(<anything>) Can only return default values for types that impl std::Default")]
#[cfg_attr(not(feature = "nightly"), ignore)]
#[cfg_attr(not(feature = "nightly"), allow(unused_must_use))]
fn return_default() {
    let mut mock = MockExternalStruct::<NonDefault>::new();
    mock.expect_foo();
    mock.foo();
}

#[test]
fn returning() {
    let mut mock = MockExternalStruct::<NonDefault>::new();
    mock.expect_foo()
        .returning(NonDefault);
    mock.foo();
}