How to check if QueryContainer has specific properties?

Question

I am generating Elasticsearch queries for the NEST Client when parsing my own simple query language. That is, the parser returns a QueryDescriptor (which is an alias for Func<QueryContainerDescriptor<SearchResult>, QueryContainer>) which then can be used to get the search results from Elasticsearch.

When the input is a query like nestedObject.someField:someValue, the following method GetQueryDescriptor with query == "nestedObject.someField:someValue" would be invoked.

// NestedObjectQueryToken.cs
public Func<QueryContainerDescriptor<SearchResult>, QueryContainer> GetQueryDescriptor(string query)
{
    // GetFieldNames() extracts the fields that the user search in from the query
    // (there could possibly be more than one field present)
    var nestedFields = query.GetFieldNames().Select(fieldName => new Field("nestedObject." + fieldName));
    return descriptor => descriptor.NestedFieldSearch(query, _ => _.Fields(fields));
}

// QueryDescriptorExtensions.cs
public static QueryContainer NestedFieldSearch(this QueryContainerDescriptor<SearchResult> descriptor,
    string query, FieldsDescriptor nestedFields)
{
    return descriptor.Nested(n => n
        .Path("nestedObject")
        .Query(sub => sub
            .QueryString(queryString => queryString
                .Query(query)
                .Fields(nestedFields))))
}

SearchResult is the class that is used for the mapping of the results.

The QueryDescriptor is later applied to a SearchDescriptor<SearchResult> so that it can be used in the Search method of NEST.

---

I expect the QueryDescriptor to have specific properties. In the example above, it should contain a nested query with its inner query's fields set to "nestedObject.someField".

Now I want to test this property with a unit test, i.e. without sending the query to a server.

How can I "look inside the QueryDescriptor" to assert that its properties are as expected?

Answer 1

You can achieve this by casting your result query container to IQueryContainer

QueryContainer Query(QueryContainerDescriptor<Document> q) =>
    q.Term(t => t.Field(f => f.Name).Value("something"));

var actual = Query(new QueryContainerDescriptor<Document>()) as IQueryContainer;

Assert.AreEqual("something", actual.Term.Value);

Hope that helps.