With an increased need for an agile and optimized project development system, programmers have a tough time dealing with the code and making it error-free.
Unit testing is a nice option for programmers to create applications with minimal errors. Be it unit testing or integrating testing, businesses need to ensure that an application offers nice and useful features and at the same be error-free.
What Is Unit Testing?
Unit testing is one of the testing methods wherein developers break coding scripts into the smallest units to quickly and easily check the functionality of single function or class. Implementation of unit testing is normally done at the development cycle of the application by the developer before passing it on to the testing team. Basically unit testing lets you know if individual functions or procedures deliver the desired output.
Benefits of Unit Testing
- It is easy to identify bugs and errors in a coding project when codes and isolated and tested. Once the code is integrated, it takes time and effort to identify bugs and errors.
- Developers write unit tests that are specific to each code unit. When changes are made to the code, it is easy to identify errors.
- As unit testing is individually done on code units, greater levels of agility in the application development can be achieved.
- Unit testing benefit the programmer and not anybody else. However, properly written unit test codes effectively prevent bugs and make the job of others easy.
- To use unit testing, you don’t need actual databases. You can use mocks or stubs to test smallest coding units.
When To Use Unit Testing?
The fullness of unit testing can be seen in modular code development that lets you create clearly focused and reusable designs. When you test an application as an entire unit, there are multiple areas that can fail. For larger applications, it is difficult to find the problem and the code responsible for the problem. When you separate different coding pieces, you can create a subset of the entire thing and test it easily. While you can quickly detect errors, resolving them and reusing code is easy and effective as well.
Consider an example when your application has to retrieve records from a database and process them. When you test the entire application, there are several areas that can fail your system. Either the retrieving code might contain errors or the processing part. At the same time, there are other technical issues involved. If there is an I/O error or a networking issue, the application cannot deliver desired results. While you can identify the problem after serious inspection, it consumes a lot of time and energy. Unit testing is the best option in this case. By using simple unit test case, you can check the retrieval process. At the same time, you can provide mock data and check the processing part. By isolating tasks, you can easily check the functionality of the program and leverage resources to enjoy agile application development. However, you should keep in mind that unit testing is a part of the application development process and it does not completely prevent bugs. You need to perform other testing methods to ensure that the application is free of errors.
Common Issues With Unit Testing
While unit tests incorporate agility into development projects, there are certain issues as well.
Unit Tests Are Too Long To Run
The chronic one is that unit tests are too long to run. This problem occurs when you develop the wrong type of testing scripts. Basically, a true unit meets these conditions:
- Does not touch a database or a file system
- Does not communicate across a network
- Should be able to run simultaneously with other tests
- Doesn’t require special environments to run tests
However, programmers tend to write long scripts to check how the application contacts and retrieves data from a database or a file system. When there are moving parts in the system, you have to stick to true unit tests. If the unit test does not separate your logic from the OS and other features, it does not serve the purpose.
As stated earlier, a true unit test does not talk to a database or a file system. Instead, you create a mock or a stub to check the functionality of the code. The MOCK verifies the calling method and the STUB returns a value. There are several mocking frameworks like .NET, C++, Python, PHP or GMock. By using any of these frameworks, you can easily create mocks. However, there are instances wherein the mock code becomes more complex than the actual project code. So, make sure to create quality code that is short, easily understandable and delivers results.
Unit Test Naming Conventions
When you write multiple unit tests, naming them in a proper way is important. If you use generic names like UT1, UT2 or testcode1 and testcode2, it becomes difficult to identify the purpose of each test. Instead, you have to use a proper criterion while naming unit tests. According to Roy Osherov’s naming standards for unit tests, the basic principle to follow while naming a unit test is
The name should talk about three things
- Requirement of the test
- Expected state or input
- Expected results or behavior
Unit Testing Vs Integration Testing
Unit tests drive your design. By testing each piece of the module, you can effectively develop the system. Moreover, they guarantee that each function performs accordingly. They are easy to maintain and you can even document workflow as well.
On the other hand, integration tests are useful when you have to test the entire application or the system as an additional layer to regression testing. You test the code with real databases and resources. In short, you use one single large test code to test multiple objects of a system. Another important area wherein integration tests are highly effective is when testing legacy code. As legacy code does not contain proper tests, it is not easy to test it. By using any legacy code testing tool like Typemock, you can run integration tests on the legacy code to ensure that components are properly integrated.
| Unit Testing | Integration Testing |
| The purpose is to verify if the smallest piece of code is delivering intended results. | The purpose is verify if various pieces of the system or application work together. |
| The scope is narrow | The scope is large and cover the entire application of a system |
| Easy to write and execute | Lot of effort needed |
| Useful only for developers | Useful for developers and other teams like QA and Helpdesk as well |
| Do not require resources like database and hardware | Requires resources like database and hardware |
| Performed in isolation | Resembles production environment |
| No dependence on code outside the test | Dependant on outside code as well |
| Test runs for few minutes | Tests can run for hours |
To effectively run tests and trust the outcome, you should distinguish and separate integration tests and unit tests for a quality development project.
Conclusion:
While the same principle cannot be applied to all projects, the basic principle of testing is as the above testing pyramid. As seen in the pyramid, unit tests form the base of the project development and take up a larger portion of tests. Integration tests are one step above unit testing wherein the entire system is checked with real-time resources followed by acceptance testing.