public async Task CheckIfCategoryExitsByIdShouldReturnCorrectBool() { var options = new DbContextOptionsBuilder <ApplicationDbContext>() .UseInMemoryDatabase(databaseName: Guid.NewGuid().ToString()).Options; var dbContext = new ApplicationDbContext(options); var repositoryCategory = new EfDeletableEntityRepository <Category>(dbContext); var category = new Category { Id = 1, Title = "test", Description = "test", Name = "test", }; await repositoryCategory.AddAsync(category); await repositoryCategory.SaveChangesAsync(); var service = new CategoriesService(repositoryCategory); var resultTrue = await service.CategoryExitsAsync(category.Id); var resultFalse = await service.CategoryExitsAsync(2); Assert.True(resultTrue); Assert.False(resultFalse); }