它应该是“排列-断言-行为-断言"吗? [英] Should it be "Arrange-Assert-Act-Assert"?

问题描述

关于布置行为断言的经典测试模式，我经常发现自己添加了一个法案之前的反主张.这样，我知道传递的断言实际上是作为操作结果传递的.

Regarding the classic test pattern of Arrange-Act-Assert, I frequently find myself adding a counter-assertion that precedes Act. This way I know that the passing assertion is really passing as the result of the action.

我认为它类似于red-green-refactor中的红色，在这种情况下，只有在测试过程中看到红色条时，我才知道绿色条表示我已经编写了使有所不同.如果我编写了通过测试，则任何代码都可以满足要求；类似地，关于安排—断言—行为—断言"，如果我的第一个断言失败，我知道任何行为都会通过最终的断言，因此实际上并没有验证有关该行为的任何内容.

I think of it as analogous to the red in red-green-refactor, where only if I've seen the red bar in the course of my testing do I know that the green bar means I've written code that makes a difference. If I write a passing test, then any code will satisfy it; similarly, with respect to Arrange-Assert-Act-Assert, if my first assertion fails, I know that any Act would have passed the final Assert - so that it wasn't actually verifying anything about the Act.

您的测试是否遵循这种模式?为什么或为什么不呢?

Do your tests follow this pattern? Why or why not?

更新澄清:初始断言本质上与最终断言相反.这不是Arrange奏效的断言.有人断言该法案尚未奏效.

Update Clarification: the initial assertion is essentially the opposite of the final assertion. It's not an assertion that Arrange worked; it's an assertion that Act hasn't yet worked.

推荐答案

下面是一个示例.

public void testEncompass() throws Exception {
    Range range = new Range(0, 5);
    assertFalse(range.includes(7));
    range.encompass(7);
    assertTrue(range.includes(7));
}

可能是我写了Range.includes()来简单地返回true.我没有，但是我可以想象我可能拥有.否则我可能以其他许多方式将其写错了.我希望并期望使用TDD可以正确地进行操作-includes()可以正常工作-但也许我没有.因此，第一个断言是一个健全性检查，以确保第二个断言确实有意义.

It could be that I wrote Range.includes() to simply return true. I didn't, but I can imagine that I might have. Or I could have written it wrong in any number of other ways. I would hope and expect that with TDD I actually got it right - that includes() just works - but maybe I didn't. So the first assertion is a sanity check, to ensure that the second assertion is really meaningful.

单独阅读，表示:断言修改后的范围包括7".在第一个断言的上下文中读到，它的意思是:断言调用contain()会使它包含7.而且由于contains是我们正在测试的单元，因此我认为这是一些(小的) )值.

Read by itself, assertTrue(range.includes(7)); is saying: "assert that the modified range includes 7". Read in the context of the first assertion, it's saying: "assert that invoking encompass() causes it to include 7. And since encompass is the unit we're testing, I think that's of some (small) value.

我接受自己的回答；许多其他人误解了我的问题，这是关于测试安装程序的.我认为这略有不同.

I'm accepting my own answer; a lot of the others misconstrued my question to be about testing the setup. I think this is slightly different.

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