public void ExecuteAsync_should_throw_when_binding_is_null()
{
var subject = new MapReduceOperation <BsonDocument>(_collectionNamespace, _mapFunction, _reduceFunction, _resultSerializer, _messageEncoderSettings);
Func <Task> act = () => subject.ExecuteAsync(null, CancellationToken.None);
act.ShouldThrow <ArgumentNullException>().And.ParamName.Should().Be("binding");
}
