Unit test with a lean arrange section. The unit test uses private methods to create the required fake instances using AutoFixture and FakeItEasy. Note that named arguments are used to clarify the meaning of the arguments.

UnitTestWithLeanArrangeSection.cs

[Fact]
public void GetHighestRatedMovies_RepositoryContainsMoviesWithRatings_ReturnsMoviesOrderedByDescendingRating()
{
    // Arrange
    IMovieRepository fakeMovieRepository = GetFakeMovieRepository(nrOfMoviesInRepository: 20);
    IMovieService movieService = new MovieService(fakeMovieRepository, context: null, logger: null);
    MovieServiceRequest request = GetMovieServiceRequest(nrOfMoviesToReturn: 5);

    // Act
    IList<Movie> movies = movieService.GetHighestRatedMovies(request);

    // Assert
    movies.Should().BeInDescendingOrder(movie => movie.Rating);
}

private static IMovieRepository GetFakeMovieRepository(int nrOfMoviesInRepository)
{
    var fixture = new Fixture();
    var movies = fixture.CreateMany<Movie>(nrOfMoviesInRepository).ToList();
    var fakeRepository = A.Fake<IMovieRepository>();
    A.CallTo(() => fakeRepository.GetAll()).Returns(movies);

    return fakeRepository;
}

private static MovieServiceRequest GetMovieServiceRequest(int nrOfMoviesToReturn)
{
    return new MovieServiceRequest
               {
                   NumberOfMoviesToReturn = nrOfMoviesToReturn
               };
}