Elasticsearch testing(unit/integration) best practices in C# using Nest

I've been seraching for a while how should I test my data access layer with not a lot of success. Let me list my concerns:

1. Unit tests

This guy (here: Using InMemoryConnection to test ElasticSearch) says that:

Although asserting the serialized form of a request matches your expectations in the SUT may be sufficient.

Does it really worth to assert the serialized form of requests? Do these kind of tests have any value? It doesn't seem likely to change a function that should not change the serialized request.

If it does worth it, what is the correct way to assert these reqests?

2. Unit tests once again

Another guy (here: ElasticSearch 2.0 Nest Unit Testing with MOQ) shows a good looking example:

void Main()
{
    var people = new List<Person>
    {
        new Person { Id = 1 },
        new Person { Id = 2 },
    };

    var mockSearchResponse = new Mock<ISearchResponse<Person>>();
    mockSearchResponse.Setup(x => x.Documents).Returns(people);

    var mockElasticClient = new Mock<IElasticClient>();
    mockElasticClient.Setup(x => x
        .Search(It.IsAny<Func<SearchDescriptor<Person>, ISearchRequest>>()))
        .Returns(mockSearchResponse.Object);

    var result = mockElasticClient.Object.Search<Person>(s => s);

    Assert.AreEqual(2, result.Documents.Count()).Dump();
}

public class Person
{
    public int Id { get; set;}
}

Probably I'm missing something but I can't see the point of this code snippet. First he mocks an ISearchResponse to always return the people list. then he mocks an IElasticClient to return this previous search response to any search request he makes.

Well it doesn't really surprise me the assertion is true after that. What is the point of these kind of tests?

3. Integration tests

Integration tests do make more sense to me to test a data access layer. So after a little search i found this (http://ift.tt/2bJZtBb) package. If I'm not mistaken this is only about an embedded JVM and an ES. Is it a good practice to use it? Shouldn't I use my already running instance?

If anyone has good experience with testing that I didn't include I would happily hear those as well.