Function contains_substring 

pub fn contains_substring<T>(expected: T) -> StrMatcher<T>

Matches a string containing a given substring.

Both the actual value and the expected substring may be either a String or a string reference.

verify_that!("Some value", contains_substring("Some"))?;  // Passes
verify_that!("Another value", contains_substring("Some"))?;   // Fails
verify_that!("Some value".to_string(), contains_substring("value"))?;   // Passes
verify_that!("Some value", contains_substring("value".to_string()))?;   // Passes

See the StrMatcherConfigurator extension trait for more options on how the string is matched.

Note on memory use: In most cases, this matcher does not allocate memory when matching strings. However, it must allocate copies of both the actual and expected values when matching strings while ignoring_ascii_case or ignoring_unicode_case are set.