Function has_entry 

pub fn has_entry<KeyT, MatcherT>(
    key: KeyT,
    inner: MatcherT,
) -> HasEntryMatcher<KeyT, MatcherT>

Matches a &HashMap containing the given key whose value is matched by the matcher inner.

let value = HashMap::from([(0, 1), (1, -1)]);
verify_that!(value, has_entry(0, eq(&1)))?;  // Passes
verify_that!(value, has_entry(1, gt(&0)))?;  // Fails: value not matched
verify_that!(value, has_entry(2, eq(&0)))?;  // Fails: key not present

Note: One could obtain the same effect by using contains and a Matcher<(&Key, &Value)>:

let value = HashMap::from([(0, 1), (1, -1)]);
verify_that!(value, contains(eq((&0, &1))))?;