Page 41 - SOFTWARE TESTING & QUALITY ASSURANCE

Software Testing and Quality Assurance

A software module checks the age of the individual who has applied for a
driving license. Any individual who is above 18 years and less than or equal to
60 years is eligible to apply for the driving license.

Condition: Eligibility criteria for driving license
Valid class: Age between 18 to 60 years
Invalid class: 1. Age below 18 years
2. Age above 60 years

Here, we have three classes -- age ‘between 18 to 60’, ‘below 18’, and ‘above 60’
years. Say, you have a test case where you want to check what the output of the
software is when you enter the age as 45. This test case falls under the case "Age
between 18 to 60 years”. The test cases that try to find the response of the
software for the ages that range from 18 to 60 will fall under this class.
Similarly, the test cases that provide the age which is less than 18 fall under the
class "Age below 18 years", and test cases that provide the age which is greater
than 60 fall under the class "Age above 60 years".

Some of the guidelines that are used to define Equivalence classes are:

1. If the test case input condition is a range, then you can define a minimum of one
valid and two invalid equivalence classes.
2. If the test case input condition is a specific value, then you can define one valid
and one invalid equivalence class.

3. If the test case input condition is a member of a set, then you can define one valid
and one invalid equivalence class.
4. If the input condition is a Boolean value, then you can define one valid and one
invalid equivalence class.
3.2.3 Data Testing

Any software can be divided into two parts, Data which consists of inputs from keyboard, mouse or
disk files, and Program which consists of code of the program which specifies the logic or syntax.
Data testing refers to testing the data, which includes the data that the user inputs to the software and
the output he/she receives. Even the intermediate values that are generated, but are not displayed on
the output device are also vital data when it comes to debugging the software. Based on the concept of
equivalence partitioning, the testing can be carried out on the following four levels.
1. Boundary conditions
2. Sub-boundary conditions
3. Nulls
4. Bad data

Boundary Conditions
Software certainly works fine under normal conditions, but it is important to test whether the software
can operate properly under extreme conditions. Every application has a limit or maximum and
minimum values it can process, and the tester has to identify these extreme limits to prepare test cases.
These extreme values are provided as inputs, and tested for occurrence of bugs. Depending on the kind
of application, the boundary conditions vary.

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