Macro lib::assert_contains

macro_rules! assert_contains {
    ($container:expr, $containee:expr $(,)?) => { ... };
    ($container:expr, $containee:expr, $($message:tt)+) => { ... };
}

Assert a container is a match for an expression.

• If true, return ().

• Otherwise, call panic! with a message and the values of the expressions with their debug representations.

Examples

// Return Ok when a string contains a substring
let a = "alfa";
let b = "lf";
assert_contains!(a, b);
//-> ()

// Return Ok when a range contains a value
let a = 1..5;
let b = 2;
assert_contains!(a, &b);
//-> ()

// Panic with error message
let result = panic::catch_unwind(|| {
let a = "alfa";
let b = "zz";
assert_contains!(a, b);
//-> panic!
});
assert!(result.is_err());
let actual = result.unwrap_err().downcast::<String>().unwrap().to_string();
let expect = concat!(
    "assertion failed: `assert_contains!(container, containee)`\n",
    " container label: `a`,\n",
    " container debug: `\"alfa\"`,\n",
    " containee label: `b`,\n",
    " containee debug: `\"zz\"`"
);
assert_eq!(actual, expect);

Module macros

• assert_contains
• assert_contains_as_result
• debug_assert_contains