Functional Testing

Functional Testing

Introduction

Functional tests are defined as scripts or programs configured to test that packages (groups of bunch of classes) meeting their exterior requirements and also achieving goals, such as the performance. This testing based on black box testing and thus for this reason, it is not concerned the source code that required by the application. Therefore, it should be highlighted that functional testing is an important technique to implement different functions in the system. Appropriate input provided for testing of each and every functionality of the system, similarly, verifying the output is necessary with comparison between the expected and the actual results is required. Functional testing involves checking and testing of User Interface, security, API Database, client/server applications and also the functionality of the Application under Test. The advantage of the testing is that it can be done both ways, that is, manually and automatically (Guru 99, 2013).

The main objective of Functional Testing is checking the functionalities of the software system that running in the operating system, therefore, the testing focuses on;

Mainline Functions; testing the central functions of the application

Basic Usability: it includes the basic usability testing of the system. Therefore, the testing based on whether the user can have difficulties in navigating through the screen or can freely move.

Accessibility: accessibility of the system is basically checked for the user.

Error Conditions: using different appropriate techniques to check the error conditions. The purpose of checking is to figure out whether suitable error messages are displayed or not (Software Testing Help, 2013).

Discussion

Three Types of Functional Testing

Following are the three different types of functional testing;

Boundary Based Testing/Analysis

Boundary based testing or boundary value analysis is based on the testing at the boundaries between different partitions. The analysis includes both, the valid boundaries and the invalid boundaries. For instance, consider the example of printer that has an input option to generate number of printed copies from 1 to 99. Therefore, in this case, to go for the boundary value analysis, the boundary set between the maximum and the minimum boundary values and also in between the valid partition (1 to 99 in the example). Similarly, the first and last value of the partition in each of the invalid partitions those are adjacent to valid partitions (0 and 100 in the given case). Therefore, in the given example, three different equivalence partition tests could be conducted with four different value tests. One important thing that needs to be considering that there is no such hard and fast rule to test only one value from each of the equivalence class that actually created for inputting domains. Therefore, one can select multiple invalid and valid values from different equivalence class according to the previous judgments and needs. The purpose of sharing this example with the readers is that it is very simple and basic to understand the concept of boundary value analysis (ISTQB Exam Certification, n.d.).

Equivalence Class Testing

Except from the most trivial of software applications used, it is normally considered impossible to test all the input combinations that ...