I have the following code that returns `Items`

    public static IList<Item> GetAll(Language language)
    {
        var index = $"my_index_{Context.Database.Name.ToLowerInvariant()}";
        using (var context = ContentSearchManager.GetIndex(index).CreateSearchContext())
        {
            var results = context.GetQueryable<SearchResultItem>()
                                 .InLanguage(language);
    
            return results.ToList();
        }
    }

I want to unit test some code that uses this function. I have set up `FakeDb` to use in the test as below:

    using (var db = new Db
    {
      new DbItem("Home") {{"Title", "Welcome!"}}
    })
    {
        sitecoreReader.GetAllThings();//this in turn calls GetAll(Language language)
    }


Now when to code hits the line `using (var context = ContentSearchManager.GetIndex(index).CreateSearchContext())` it throws the error below:

> Sitecore.ContentSearch.Exceptions.IndexNotFoundException

Google is not helping me on this one...