public async Task ProcessingRecipeShouldYieldUniqueIdsForSteps() { var recipeParser = new JsonRecipeParser(); List<RecipeStepDescriptor> recipeSteps = new List<RecipeStepDescriptor>(); await recipeParser.ProcessRecipeAsync(_fileInfo.CreateReadStream(), (descripor, stepDescriptor) => { recipeSteps.Add(stepDescriptor); return Task.CompletedTask; }); // Assert that each step has a unique ID. Assert.True(recipeSteps.GroupBy(x => x.Id).All(y => y.Count() == 1)); }