Fill SortedDictionary

[ploeh]

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

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

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

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

Since AutoFixture can already supply non-empty dictionaries, and one of the constructor overloads for SortedDictionary<TKey, TValue> takes a dictionary, it ought to be fairly easy to add a relay from SortedDictionary<TKey, TValue> to IDictionary<TKey, TValue>.

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

Another implementation option is to mimic the way concrete dictionaries are already filled. See the combination of DictionaryFiller and DictionarySpecification in the Fixture class.

[ploeh]

See also #622 and #624.

[rahulpnath]

@ploeh Do you have any thoughts on how to support custom comparer for the SortedDictionary Key.

I just started on with this. It works fine for types that have a default comparer, but fails for complex types, objects etc. Would going down creating a custom request object with the comparer as a property be the right path.

[ploeh]

Could the feature be implemented similar to ##629? Since that implementation chose the Specification options, I'd prefer it if this and #622 use the same approach, if at all possible.

[rahulpnath]

@ploeh Cool will use the Specification approach. But even with the sorted set specification approach, I don't see how this would work?

var result = fixture.Create<SortedSet<object>>();

It fails with below error (as expected)
Test 'Ploeh.AutoFixtureUnitTest.FixtureTest.CreateSortedSetReturnsCorrectResult' failed: System.Reflection.TargetInvocationException : Exception has been thrown by the target of an invocation.
---- System.InvalidOperationException : Failed to compare two elements in the array.
-------- System.ArgumentException : At least one object must implement IComparable.

Is that the expected behavior?

[ploeh]

What is it creating?

[rahulpnath]

@ploeh Sorry that got trimmed in markdown formatting

Updated it SortedSet of object or any type that does not have a default comparer

[ploeh]

Is the situation different from when one requests IDictionary<TKey, TValue>?