[英]Ensure that a trait implementation in rust satisfy properties
I am making a trait to define a distance in a metric space like: 我正在制作一个特征来定义度量空间中的距离,例如:
trait Metric<T> {
fn distance(o1: &T, o2: &T) -> f64;
}
and I want that any implementation satisfy some properties, for example: 并且我希望任何实现都满足某些属性,例如:
distance(o, o) = 0.0
Exist a way in rust to enforce that? 存在一种强制执行的方法吗?
You can use the trait_tests
crate , though I do believe the crate is merely an experiment, so there may be rough edges. 您可以使用trait_tests
板条箱 ,尽管我确实认为该板条箱仅仅是实验,所以可能会有粗糙的边缘。 Specifically, I couldn't figure out how to actually test all implementations of Metric<T>
, rather only for a concrete type, Metric<i32>
. 具体来说,我无法弄清楚如何实际测试Metric<T>
所有实现,而只能针对具体类型Metric<i32>
。
For your example: 例如:
use trait_tests::*;
pub trait Metric<T> {
fn distance(o1: &T, o2: &T) -> f64;
}
#[trait_tests]
pub trait MetricTests: Metric<i32> {
fn test_distance() {
// These could possibly be extended using quickcheck or proptest
assert!(Self::distance(&42, &42) == 0.0);
}
}
struct CartesianPlane {}
#[test_impl]
impl Metric<i32> for CartesianPlane {
fn distance(o1: &i32, o2: &i32) -> f64 {
(*o2 - *o1) as f64
}
}
Then cargo test
should include the auto-generated test for the implementors of the trait that are annotated with #[test_impl]
. 然后, cargo test
应包括针对该特性的实现者的自动生成的测试,并用#[test_impl]
进行注释。
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