Fill SortedSet

[ploeh]

When you ask AutoFixture for a hash set, it provides a non-empty value:

var fixture = new Fixture();
var actual = fixture.Create<HashSet<string>>();
Assert.NotEmpty(actual); // Succeeds

When you request a sorted set, on the other hand, the returned set is empty. This test fails its assertion:

var fixture = new Fixture();
var actual = fixture.Create<SortedSet<string>>();
Assert.NotEmpty(actual); // Fails

Since AutoFixture can already supply non-empty collections, and one of the constructor overloads for SortedSet<T> takes a IEnumerable<T>, it ought to be fairly easy to add a relay from SortedSet<T> to IEnumerable<T>.

The implementation could for example be a new ISpecimenBuilder that handles requests for any SortedSet<T> by resolving IEnumerable<T> from the context, and then invoking the appropriate constructor overload with the returned value.

Another implementation option is to mimic the way hash sets are already filled. See the combination of EnumerableFavoringConstructorQuery and HashSetSpecification in the Fixture class.

[ploeh]

See also #622 and #623.