Unit Testing For Developers


This article gives you a clear picture about Unit Test and its benefits; nowadays unit testing has become a greater part of software application development, so let’s understand why a developer has to do a unit test and also how will it be useful for developers to deliver a bug-free better quality of code.


Source: wouterdekort.com

What is Unit Testing?

Unit testing is a software testing method by which individual units of source code, sets of one or more computer program modules together with associated control data, usage procedures, and operating procedures, are tested to determine whether they are fit for use.

Intuitively, one can view a unit as the smallest testable part of an application. In procedural programming, a unit could be an entire module, but it is more commonly an individual function or procedure. In object-oriented programming, a unit is often an entire interface, such as a class, but could be an individual method.

Unit tests are short code fragments created by programmers or occasionally by white box testers during the development process. It forms the basis for component testing.

Why do Unit Testing?

Data from projects says that in spite of apparent progress many software projects fail and most are completed late or over budget due to lack of quality or integration issues. Software development teams need to respond faster to deliver the software the organization needs, where it results in the lack of Unit Testing in early phase of development.

Let's see the various Benefits of the Unit Test during the software application development phase, as follows,

Faster Delivery of Code:

Most of the development and QA cycles are consumed coddling fragile legacy applications. The drag from ongoing problems in legacy code slows down the organization, making it harder to meet its commitments.

Higher quality of Code:

Teams often release code with more bugs than they would like, leading to longer and more expensive QA cycles and more bugs delivered to end users. There's been too much focus on testing to remove bugs, instead of building software without bugs in the first place.

More (Agile) flexibility:

The legacy systems are too fragile and too inflexible to enhance. It’s hard to be agile as a business if you’re afraid to change the code on which the business depends.

What can you do to build better code and make the code that you already have better - so that you can deliver more software, faster?

The only answer is "Unit Testing" for better code quality, Bug-free delivery and exact estimated time and cost and mostly to avoid over spending.


Source: embeddedinsights.com

How to do Unit Testing?

A unit test is code that exercises a specific portion of your codebase in a particular context. Typically, each unit test sends a specific input to a method and verifies that the method returns the expected value, or takes the expected action.

Unit tests prove that the code you are testing does in fact do what you expect it to do.

You should strive to increase the state coverage of your unit tests. Code has many more possible states than it has lines of code.

You wouldn’t want to test all of the different states for this program. Instead, you should probably test a few different inputs for this method, even if it means that you will have achieved 100% code coverage several times over.

Different states of Testing:

There are three different states that you might consider testing, they are as follows,

  1. Positive input
  2. Negative input
  3. 0 input

Testing with a positive input and with a negative input will behave as expected. Testing with a 0 input however will yield a surprise error or some kind of exception like System.MathException.

Unit testing involves only those characteristics that are important to the performance of the unit under test. This encourages developers to modify the source code without immediate concerns about how such changes might affect the functioning of other units or the program as a whole.

Once all of the units in a program have been found to be working in the most efficient and error-free manner possible, larger components of the program can be evaluated by means of integration testing.

Unit testing can be time-consuming and tedious. [As a developer even I too felt many times], however It demands patience and thoroughness on the part of the development team.

Rigorous documentation must be maintained. Unit testing must be done with an awareness that it may not be possible to test a unit for every input scenario that will occur when the program is run in a real-world environment.