/// Asserts that the [FinderBase] matches nothing in the available candidates.
///
/// ## Sample code
///
/// ```dart
/// expect(find.text('Save'), findsNothing);
/// ```
///
/// See also:
///
///  * [findsAny], when you want the finder to find one or more candidates.
///  * [findsOne], when you want the finder to find exactly one candidate.
///  * [findsExactly], when you want the finder to find a specific number of candidates.
///  * [findsAtLeast], when you want the finder to find at least a specific number of candidates.
const Matcher findsNothing = _FindsCountMatcher(null, 0);

/// Asserts that the [Finder] locates at exactly one widget in the widget tree.
///
/// This is equivalent to the preferred [findsOne] method.
///
/// ## Sample code
///
/// ```dart
/// expect(find.text('Save'), findsOneWidget);
/// ```
///
/// See also:
///
///  * [findsNothing], when you want the finder to not find anything.
///  * [findsAny], when you want the finder to find one or more candidates.
///  * [findsExactly], when you want the finder to find a specific number of candidates.
///  * [findsAtLeast], when you want the finder to find at least a specific number of candidates.
const Matcher findsOneWidget = _FindsCountMatcher(1, 1);