public async Task ContainsByIdAsync_WithValidId_ShouldReturnTrue() { var subCategoryName = "test"; var subCategory = new SubCategory() { Name = subCategoryName, CategoryId = "test", }; await context.SubCategories.AddAsync(subCategory); await context.SaveChangesAsync(); var subCategoryFromDb = await context.SubCategories.FirstOrDefaultAsync(s => s.Name == subCategoryName); var result = await service.ContainsByIdAsync(subCategoryFromDb.Id.ToString()); Assert.IsTrue(result); }