Macro assert_matches::assert_matches

macro_rules! assert_matches {
    ( $e:expr , $pat:pat ) => { ... };
    ( $e:expr , $pat:pat if $cond:expr ) => { ... };
    ( $e:expr , $pat:pat , $($arg:tt)* ) => { ... };
    ( $e:expr , $pat:pat if $cond:expr , $($arg:tt)* ) => { ... };
}

Asserts that an expression matches a given pattern, with an optional guard expression.

#[macro_use] extern crate assert_matches;

#[derive(Debug)]
enum Foo {
    A(i32),
    B(i32),
}

let a = Foo::A(1);

assert_matches!(a, Foo::A(_));

assert_matches!(a, Foo::A(i) if i > 0);