public async Task AddRangeAsync_Test() { var options = new DbContextOptionsBuilder <ApplicationContext>() .UseInMemoryDatabase(databaseName: "AddTestDatabase") .Options; using (var context = new ApplicationContext(options)) { context.Database.EnsureCreated(); var repository = new CourseRepository(context); var newCourses = new List <Course> { new Course { Name = "New", LecturerId = 1 }, new Course { Name = "New", LecturerId = 2 } }; var prevCount = repository.GetAll().Count(); await repository.AddRangeAsync(newCourses); await context.SaveChangesAsync(); var courses = repository.GetAll(); Assert.That(courses.Count(), Is.EqualTo(prevCount + 2)); } }