From 09153f3085ba82668d15936df5b41c8cbd407841 Mon Sep 17 00:00:00 2001 From: DarkSun Date: Fri, 5 Feb 2021 05:04:43 +0800 Subject: [PATCH] =?UTF-8?q?=E9=80=89=E9=A2=98[tech]:=2020210204=20How=20to?= =?UTF-8?q?=20implement=20business=20requirements=20in=20software=20develo?= =?UTF-8?q?pment?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit sources/tech/20210204 How to implement business requirements in software development.md --- ...ss requirements in software development.md | 128 ++++++++++++++++++ 1 file changed, 128 insertions(+) create mode 100644 sources/tech/20210204 How to implement business requirements in software development.md diff --git a/sources/tech/20210204 How to implement business requirements in software development.md b/sources/tech/20210204 How to implement business requirements in software development.md new file mode 100644 index 0000000000..1527f6babe --- /dev/null +++ b/sources/tech/20210204 How to implement business requirements in software development.md @@ -0,0 +1,128 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: url: ( ) +[#]: subject: (How to implement business requirements in software development) +[#]: via: (https://opensource.com/article/21/2/exceptional-behavior) +[#]: author: (Alex Bunardzic https://opensource.com/users/alex-bunardzic) + +How to implement business requirements in software development +====== +Increment your e-commerce app to ensure it implements required business +process rules correctly. +![Working on a team, busy worklife][1] + +In my previous articles in this series, I explained why tackling coding problems all at once, as if they were hordes of zombies, is a mistake. I'm using a helpful acronym to explain why it's better to approach problems incrementally. **ZOMBIES** stands for: + +**Z** – Zero +**O** – One +**M** – Many (or more complex) +**B** – Boundary behaviors +**I** – Interface definition +**E** – Exercise exceptional behavior +**S** – Simple scenarios, simple solutions + +In the first three articles in this series, I demonstrated the first five **ZOMBIES** principles. The first article [implemented **Z**ero][2], which provides the simplest possible path through your code. The second article performed [tests with **O**ne and **M**any][3] samples, and the third article looked at [**B**oundaries and **I**nterfaces][4]. In this article, I'll take a look at the penultimate letter in our acronym: **E**, which stands for "exercise exceptional behavior." + +### Exceptional behavior in action + +When you write an app like the e-commerce tool in this example, you need to contact product owners or business sponsors to learn if there are any specific business policy rules that need to be implemented. + +Sure enough, as with any e-commerce operation, you want to put business policy rules in place to entice customers to keep buying. Suppose a business policy rule has been communicated that any order with a grand total greater than $500 gets a percentage discount. + +OK, time to roll up your sleeves and craft the executable expectation for this business policy rule: + + +``` +[Fact] +public void Add2ItemsTotal600GrandTotal540() { +        var expectedGrandTotal = 540.00; +        var actualGrandTotal = 0.00; +        Assert.Equal(expectedGrandTotal, actualGrandTotal); +} +``` + +The confirmation example that encodes the business policy rule states that if the order total is $600.00, the `shoppingAPI` will calculate the grand total to discount it to $540.00. The script above fakes the expectation just to see it fail. Now, make it pass: + + +``` +[Fact] +public void Add2ItemsTotal600GrandTotal540() { +        var expectedGrandTotal = 540.00; +        Hashtable item = [new][5] Hashtable(); +        item.Add("00000001", 200.00); +        shoppingAPI.AddItem(item); +        Hashtable item2 = [new][5] Hashtable(); +        item2.Add("00000002", 400.00); +        shoppingAPI.AddItem(item2); +        var actualGrandTotal = shoppingAPI.CalculateGrandTotal(); +        Assert.Equal(expectedGrandTotal, actualGrandTotal); +} +``` + +In the confirmation example, you are adding one item priced at $200 and another item priced at $400 for a total of $600 for the order. When you call the `CalculateGrandTotal()` method, you expect to get a total of $540. + +Will this microtest pass? + + +``` +[xUnit.net 00:00:00.57] tests.UnitTest1.Add2ItemsTotal600GrandTotal540 [FAIL] +  X tests.UnitTest1.Add2ItemsTotal600GrandTotal540 [2ms] +  Error Message: +   Assert.Equal() Failure +Expected: 540 +Actual: 600 +[...] +``` + +Well, it fails miserably. You were expecting $540, but the system calculates $600. Why the error? It's because you haven't taught the system how to calculate the discount on order totals larger than $500 and then subtract that discount from the grand total. + +Implement that processing logic. Judging from the confirmation example above, when the order total is $600.00 (which is greater than the business rule threshold of an order totaling $500), the expected grand total is $540. This means the system needs to subtract $60 from the grand total. And $60 is precisely 10% of $600. So the business policy rule that deals with discounts expects a 10% discount on all order totals greater than $500. + +Implement this processing logic in the `ShippingAPI` class: + + +``` +private double Calculate10PercentDiscount(double total) { +        double discount = 0.00; +        if(total > 500.00) { +                discount = (total/100) * 10; +        } +        return discount; +} +``` + +First, check to see if the order total is greater than $500. If it is, then calculate 10% of the order total. + +You also need to teach the system how to subtract the calculated 10% from the order grand total. That's a very straightforward change: + + +``` +`return grandTotal - Calculate10PercentDiscount(grandTotal);` +``` + +Now all tests pass, and you're again enjoying steady success. Your script **Exercises exceptional behavior** to implement the required business policy rules. + +### One more to go + +I've taken us to **ZOMBIE** now, so there's just **S** remaining. I'll cover that in the exciting series finale. + +-------------------------------------------------------------------------------- + +via: https://opensource.com/article/21/2/exceptional-behavior + +作者：[Alex Bunardzic][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://opensource.com/users/alex-bunardzic +[b]: https://github.com/lujun9972 +[1]: https://opensource.com/sites/default/files/styles/image-full-size/public/lead-images/team_dev_email_chat_video_work_wfm_desk_520.png?itok=6YtME4Hj (Working on a team, busy worklife) +[2]: https://opensource.com/article/21/1/zombies-zero +[3]: https://opensource.com/article/21/1/zombies-2-one-many +[4]: https://opensource.com/article/21/1/zombies-3-boundaries-interface +[5]: http://www.google.com/search?q=new+msdn.microsoft.com