Macro assert_str_contains

macro_rules! assert_str_contains {
    ($str:expr, $expected:expr) => { ... };
    ($str:expr, $expected:expr, $($fmt_args:tt)+) => { ... };
}

Available on crate feature test-util only.

Asserts that a given string value $str contains a substring $expected.

This macro can also take a custom panic message with formatting.