Before any software product releases, it goes through various levels of testing to make sure that it is working properly. These levels identify missing areas and prevent overlap and repetition between the development of life cycle phases. In a software development lifecycle models, there are defined phases like requirement gathering and analysis, design, coding or implementation, testing, and deployment. Each phase defines a different level of testing. The four levels of software testing are as follows.
- Unit Testing
- Integration Testing
- System Testing
- Acceptance Testing
Let us now understand what happens in each level one-by-one.
1. Unit Testing
Under this type of testing, individual sections or parts of software or product are to be tested. This testing is performed at developers end to make sure that their code is working well and meets the specifications as mentioned by the user. The ultimate aim of a Unit Testing is to divide every part of the program and test that the separate part is working perfectly. In addition to testing units separately, this testing also performs several other functions like;
- It ensures that all the statements in the unit have been executed at least once
- It ensures that data structures that represent relationships among individual data elements
- It checks all arithmetic calculations present in the unit with all possible combinations of input values.
2. Integration Testing
This testing allows individuals the opportunity to combine all of the units within the program and test them as a group. This testing is designed to find interface defects between the modules/functions. It basically checks the data flow from one module to other modules. The ultimate purpose of Integration Testing is to expose faults and interaction between integrated units. Some other points with regards to integration testing are listed below;
- It ensures that all modules work together properly and transfer accurate data across their interface
- It is performed with an intention to uncover errors that lie in the interface among the integrated components
3. System Testing
In this type of testing, the system is tested against non-functional requirements such as accuracy, reliability, and speed. The main purpose of this testing is to validate and verify the functional design specifications and to check how integrated modules work together. System Testing is performed in an environment that closely mirrors production. The testing is considered to be complete when the output is produced by the software and the outputs expected by the users are either in line or the difference between the two is within permissible range as specified by the user.
4. Acceptance Testing
Acceptance Testing is conducted to find if the requirements of a specification or contract are met as per its delivery. Under this testing, the team will utilize a variety of methods, such as pre-written scenarios and test cases to test the software and use there results obtained from these tools to find ways in which the system can be improved. The advantages of acceptance testing are;
- It gives the user an opportunity to ensure that the software meets the user requirements before accepting it from the developer
- It determines the readiness of the software to perform the operations
- It decreases the possibility of software failure to a large extent
These testing levels cannot be applied haphazardly during the development. There is a logical sequence that should be adhered to in order to minimize the risk of bugs cropping up just before the launch date.
The software testing cycle is a time-consuming process that involves various methodologies and techniques. Testers and developers use their experience and knowledge to create products that are of exceptional quality and are designed as per the requirement of the clients. However, the most integral part of the software development process is testing, which is executed in the software through several levels. At 99tests, we believe in presenting the perfect product for you. Our qualified team of testers has years of experience in software testing services and can make sure that the product is free from bugs.