Testing any software prior to launching it is essential. There are numerous software testing methods, including manual, automated, dynamic, mutation, and so on. Mutation testing is a kind of white-box testing. So, if you want to know more about Mutation testing and its types, then read this post. In this post, we shall discuss different types of mutation testing methods that are available for your perusal. So, let’s get started…
First off, let’s understand mutation testing in detail. Here we go…
Mutation testing is one of the methods of testing software. This testing technique evaluates the quality of test suites by making small changes, or ‘mutations’ to the source code of a program. These mutations are typically small, deliberate faults injected into the code, such as altering a conditional statement or modifying an operator. Mutation testing aims to see if the test program detects hidden defects or mutants. This process consists of many types of mutations to generate upgraded and effective sources of code.
The mutation testing technique involves purposefully making some changes to the source code to detect if the test program can identify changes. Essentially, these changes, also known as mutations are small and intended to cause faults in the program. The objective of mutation testing is to assess the efficiency and quality of the test program. This helps developers locate weaknesses if they fail to detect errors or faults in the source code. This technique helps improve the quality of the test cases as it identifies gaps in the testing process, helping developers build more robust and error-free software.
The History of Mutation Testing
In 1971, Richard Lipton proposed the concept of “Program Mutation.” He introduced the concept of measuring the robustness of test cases. But, due to the high costs involved in its execution, it lost its significance. Later, in the year 1978, DeMillo, Lipton, and Sayward developed it further. They formalized it as a way to evaluate the effectiveness of test cases.
The early concepts of mutation testing were limited as the techniques during that time were not robust. It is worth noting that the process of creating and testing multiple mutations is resource-intensive. However, with advancements in computing devices and the availability of automated testing tools, mutation testing became more feasible and practical.
Now, again, this method of testing has started to gain traction among developers. It has now evolved as a robust testing method. Today, there are numerous tools available to optimize the mutation process. It is now recognized as a valuable technique for identifying weaknesses in test suites and ensuring that software is thoroughly tested, contributing to the production of higher-quality software systems. It is considered one of the most important software testing methods for languages such as XML and Java. Furthermore, it is applied to design models, databases, tests, and specifications.
Do you want to know what mutation testing in software testing is in detail? If yes, we have got you covered.
What Is Mutant in Software Testing?
A mutant in software testing is a modification in the source code such as the deletion or duplication of a statement, one operator for another substitution, changes of true or false expressions, or variable modification. The source code with these mutants is then tested and results are compared to the original code. These mutants assist in discovering the efficacy of the test suite. Subsequently, testers learn how they can improve their tests.
What is the Mutation Score in Software Testing?
The Mutation Score in software testing is a metric that is used to evaluate the effectiveness of a test suite. The calculation of the mutation score can assist you in analyzing the software test’s quality. You can find loopholes in the program. Additionally, you can put efforts in the right direction to automate the better test suite. In simple terms, the mutation score is the percentage of the mutants killed with the mutants’ total number.
Mutation testing is calculated by determining the ratio of “killed” mutants to the total number of mutants generated during mutation testing. A mutant is considered “killed” if the test suite successfully detects the error introduced by the mutation, causing a test to fail.
The Formula for the Mutation Score
Mutation Score = (Number of Killed Mutants/ Total Number of Mutants x100)
Example
If developers generate 80 mutants and 75 of them are killed by the test suite, the Mutation Score would be approximately 93%.
Understanding The Importance Of Mutation Score
A high Mutation Score indicates that the test suite is effective at detecting errors. This simply implies that most of the potential bugs introduced by mutations are successfully detected and killed. On the contrary, a low Mutation Score indicates that the test suite contains gaps and that errors are left in the test suite. Developers can implement a thorough or additional test case to detect and kill the remaining mutants. All in all, the Mutation Score helps software developers assess and improve the quality and robustness of their testing efforts.
The most notable thing about this is that you can generate the calculation score for the whole software base or individual files. The maximum score that your test suite can achieve is 100. However, this maximum score is impossible to achieve because there always remain at least some loopholes in the program. Hence, the test suite should try to gain a maximum score. Conversely, a low mutation score indicates that the software testing needs more improvements. You should write different assertions or automate the test suite to overcome such issues.
Gaining a maximum mutation score can be time-consuming and exhausting. However, a high score is vital to ensure the high quality of software in many circumstances like safety-centered software or mission-targeted software.
Let’s now take a look at various types of mutation testing. Here we go…
Types of Mutation Testing
Following are the types of mutation testing that ensure qualitative software development and protection against regressions. Take a look…
1. Statement Mutation
Statement mutation refers to the alteration or deletion of statements in the code. This is an ideal mutation for testing small programs.
For instance, if the original statement is A=110 < B=200. Then, the changed code is B=110D.
2. Value Mutation
In this type of mutation, the developer changes the values of constants to detect errors or faults in the program. Usually, the higher value is replaced with the smaller value and vice versa.
Here is an example: A=5 is changed to A=10 or A=15.
3. Decision Mutation
In decision mutation, the arithmetic or logical operators are changed to recognize fault. Then, further action is taken to rectify the problem.
Example of Decision Mutation: CD.
The Bottom Line
So, this is all about Mutation Testing in Software testing and its types. The effectiveness of software depends on the quality of the database. Mutation testing is the best way to reveal hidden flaws and implement effective troubleshooting tips. It assists engineers in understanding the underlying rationale for software testing’s failure. Thanks for reading this post. Hopefully, this article has been enlightening and helped you understand the ins and outs of mutation testing.
