C++ Unit Testing

Benefits of Unit Testing in Software Development

In the previous section, we briefly discussed Unit Testing in software development. This section will discuss the benefits of unit testing in software development.

Easier Debugging

Unit testing helps identify bugs and errors in the software and stops them from propagating to a higher level. This helps save developers time spent in debugging in later stages of development.

Proper Functionality

By generating tests for Unit testing of our program, we can ensure that the program we have written performs the same way as we intended. We can also ensure that our code gets all edge cases for unexpected behavior.

Better Code Quality

Unit testing helps in increasing the code quality of the application. If the units are well-tested, they have a better chance of functioning correctly and producing the expected results.

Better Understanding of the code

Since the developers have to create the test themselves, they better understand the codebase. This helps increase confidence in the program and fewer unexpected errors on deployment.

Cost and Time

Proper Unit testing ensures that the code is free from errors and bugs and saves time and cost for debugging in the long run. Testing individual components is much easier than testing the whole program.

Types of C++ Unit Testing

Now that we know about Unit Testing in general, we will look at the methods of Unit Testing in C++ in this section. In C++, there are many approaches for unit testing, but they can be broadly categorized into framework-based testing and framework-less testing (custom testing). In framework-based testing, we use the framework with specific tools designed for writing test cases. This simplifies the process of generating and executing test cases. On the other hand, in framework-less testing, the developer generally writes the tests to cover the edge cases that can be left in automated testing. Let us now discuss each of them in more detail.

Framework-based Unit Testing

In framework-based unit testing, the testing framework provides a structured approach for writing and executing test cases. Some popular frameworks used for unit testing include Google Test(GTest), Catch2, and Boost.Test. These frameworks have tools and support for unit testing in C++. Framework-based testing helps to save the hassle of generating the test cases manually with the help of APIs.

Framework-less Unit Testing

Another method for unit testing is without using any framework to write test cases. This type of testing is generally applicable to small-scale projects. As the size of the project increases, it becomes challenging to write test cases manually for each "unit" of the application. An example to show manual unit testing is shown below.
 

Code

#include <assert.h>
#include <bits/stdc++.h>

// Function to check if two numbers are equal
int check_equal(int a, int b) {
	return (a==b);
}

// Main function
int main(int argc, char *argv[]) {

	assert(1 == check_equal(1, 1));
	assert(0 == check_equal(-1, -2));
	assert(0 == check_equal(0, 0));
	return 0;
}

You can also try this code with Online C++ Compiler

Run Code

Output

Explanation

In the above example, we have a helper function check_equal which checks if two numbers are equal and returns true if the condition is satisfied. In the main function, we have three assert statements. An assert macro is a debugging tool in C++ that allows us to test our test cases and stops the execution if any statement is not equal to the assertion expression.

The first statement returns true since 1 equals 1, and the assert expression is also set to true. Similarly, the second statement returns true because -1 is not equal to -2, and the check_sum function returns false, but the assert expression is also set to false.

However, the check_sum function returns true in the third statement because 0 equals 0. But the assert expression is set to false. Hence the return value does not match the assert expression, and the execution is stopped.

Difference between Framework-based and Framework-less testing

The main differences between framework-based and framework-less testing are given below in tabular format.

Frequently Asked Questions

What are the benefits of using frameworks in unit testing?

By using frameworks, we can make the generation process much easier. Frameworks provide a structured way of writing and executing test cases. Frameworks reduce the quantity of repetitive work required in generating test cases.

Which languages other than C++ support Unit Testing?

Unit Testing is a widely used process in the software industry. It is supported in most popular programming languages like Java, Python, JavaScript, PHP, Swift, etc. Each of these languages provides its own set of frameworks and tools.

Is it possible to replace custom testing completely with framework-based testing?

Generally, relying entirely on framework-based testing is not a good practice. Sometimes automated tests cannot capture bugs and issues which can be found by custom manual testing.

Conclusion

In this article, we discussed C++ Unit Testing. We briefly discussed what Unit testing is in general and the importance of Unit Testing in Software Development. We also discussed the benefits of unit testing in software development and the types of unit testing in C++. In the end, we concluded by discussing some frequently asked questions.

So now that you have learned about C++ Unit Testing, you can refer to similar articles.
 

• Unit Testing
   
• Backend Unit Testing
   
• Different Types of Testing in Software
   

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