How to write a good unit test case

Cucumber makes you a better developer by helping you see your code through the eyes of the user.

How to write a good unit test case

When we write automated tests either unit or integration tests for our application, we should notice pretty soon that Many test cases use the same configuration which creates duplicate code.

Building objects used in our tests creates duplicates code. Writing assertions creates duplicate code. The first thing that comes to mind is to eliminate the duplicate code. Every piece of knowledge must have a single, unambiguous, authoritative representation within a system. So we get to work and remove the duplicate code by creating a base class or classes which configures our tests and provides useful testing utility methods to its subclasses.

Unfortunately, this is a very naive solution. Keep on reading and I will present three reasons why we should not use inheritance in our tests. The point of inheritance is to take advantage of polymorphic behavior NOT to reuse code, and people miss that, they see inheritance as a cheap way to add behavior to a class.

When I design code I like to think about options. When I inherit, I reduce my options. I am now sub-class of that class and cannot be a sub-class of something else. I have permanently fixed my construction to that of the superclass, and I am at a mercy of the super-class changing APIs.

My freedom to change is fixed at compile time. Although Misko Hevery was talking about writing testable code, I think that this rule applies to tests as well.

Writing System Test Cases

Polymorphism is the provision of a single interface to entities of different types. This is not why we use inheritance in our tests.

We use inheritance because it is an easy way to reuse code or configuration. This makes our tests very hard to read. Our test classes are in the mercy of their superclass esand any change which we make to a such superclass can effect its every subclass.

So, why does this matter? It matters because tests are code too! That is why this rule applies to test code as well. By the way, did you know that the decision to use inheritance in our tests has practical consequences as well?

Inheritance Can Have a Negative Effect to the Performance of Our Test Suite If we use inheritance in our tests, it can have a negative effect to the performance of our test suite.

In order to understand the reason for this, we must understand how JUnit deals with class hierarchies: Before JUnit invokes the tests of a test class, it looks for methods which are annotated with the BeforeClass annotation.

It traverses the whole class hierarchy by using reflection. After it has reached to java. Object, it invokes all methods annotated with the BeforeClass annotation parents first. Before JUnit invokes a method which annotated with the Test annotation, it does the same thing for methods which are annotated with the Before annotation.

After JUnit has executed the test, it looks for method which are annotated with the After annotation, and invokes all found methods.

A Simple Unit Test

After all tests of a test class are executed, JUnit traverses the class hierarchy again and looks for methods annotated with the AfterClass annotation and invokes those methods.

In other words, we are wasting CPU time in two ways:For Test Case 1 of Book Order Use Case, you will have a table like that shown in Table 5.

how to write a good unit test case

This will be a document that you give to a tester. The tester will follow the directions from columns 2 and 3, and record the results in columns 5, 6, and 7. How to write “good” unit tests?

since the number of possible inputs and results are too large to just test every case, and the methods themselves are often quite longish and can not be easily be refactored without sacrificing performance.

A good unit test doesn't mirror the function it is testing.

Deliverable: System Test Scripts Writing Unit Tests for Existing JavaScript 13 Jul edit My team at Bazaarvoice has been spending a lot of time lately thinking about quality and how we can have greater confidence that our software is working as it should. We've long had functional tests in place that attempt to ask questions like "When a user clicks a button, will The Widget do The Thing?
Three Reasons Why We Should Not Use Inheritance In Our Tests He looks at some approaches that can make writing unit tests easier and more efficient for C programmers. While I can't help conquer the "boring" part, this article will look at approaches that make writing unit tests easier so that you're more inclined to do it.
Hello Cucumber Example This is usually the smallest unit of testing.

As a greatly simplified example. Test Case Template and Examples Software Engineering – Dr Ghazy Assassa Page 2 of 5. Each unit test method in your JUnit test case file should test a particular small aspect of the behavior of the "class under test." For example, an ArrayIntListTest might have one testing method to see whether elements can be added to the list and then retrieved.

This article shows how to craft good unit tests. It explores the proper structure of unit tests, the code scenarios that unit tests should cover, and the properties of well-written unit tests.

you can write a unit test for it, you can fix the bug, and the bug can never make it to production again because the unit tests will catch it in the. A simple test class will establish the target class test framework, it will verify the presence and correctness of both the build environment, the unit testing environment, the execution environment and the coverage analysis tool, and it will prove that the target class is part of the assembly and that it .

Tips for Easier Unit Testing in C# -- Visual Studio Magazine