Description
Overview
This laboratory assignment will serve as a practical introduction to rudimentary black-box testing techniques. Students will employ simplistic methods such as dirty testing, error guessing, and partition testing to get a feel for test case development and execution.
Introduction to black-box testing
Black-box testing is realized with respect to software specifications where no knowledge of the internal structure or implementation details are known. In this scenario, the application under test is the “black box”.
A set of conditions, frequently inputs, is referred to as a test case. Once a test case has been implemented, it is evaluated against the application under test, and the results are recorded. It may take many different test cases to determine whether the requirements of the system are fully satisfied. Sets of test cases are organized into test suites, where a test suite fulfils some higher level testing requirement.
Although there are an extensive number of black-box testing techniques, in this laboratory experiment we will concentrate on two categories: a) Failure testing/ error guessing, and b) Partition based testing. The following sections will briefly outline each of these categories.
Failure/Dirty Testing
- Test every possible input/action a user can perform on the system to demolish the software
- Think diabolically
- Look at every input
- Be creative; consider the user as someone from another planet
- Examples: divide by zero, wrong input type, missing values
Error Guessing
- Intuition, Innovation, Experience
- Intelligently guess at likely error location
- Use your knowledge as a programmer to explore likely areas of mistakes
- Look for common mistakes, eg rounding errors or invalid inputs
Partition Based Testing
- Cover as many possibilities as possible with as few test cases as possible
- Group together inputs for which the application is likely to behave the same
- Test equivalent inputs as a group to reduce the number of test cases
- Equivalent inputs are defined in terms of logical partitions of the input space
Equivalence Partitioning is designed to minimize the number of required test cases by forming partitions or equivalence classes of the input space. Test cases are selected in such a way that all equivalence classes are covered. Equivalence classes are sets of inputs for which we expect the system to behave the same, logically. Eg. Positive integers, geometric categorizations, numbers of inputs etc.
Boundary value analysis is a category of testing where we develop test cases that are concerned with the boundaries of equivalence classes. Boundaries are those points at which the behavior of a system is expected to change.
Preparation:
Prepare test cases for the two tasks you will be working on during the lab session. For the calculator, each test case should include 4 columns: Test ID (an incrementing number), Description (a brief explanation of the test), Expected Result, and Actual Result. For the triangle program each test case should include 7 categories: Test ID, Inputs a, b, and c, Description, Expected Result, Actual Result. In this scenario the values for a, b, and c. During the lab session you should:
- Create test cases for the specified functions of the calculator program
- For Failure testing
○ For Error guessing
- Identify all equivalence classes for the triangle program’s input space
- Formally define the requirements and boundaries of each of these equivalence classes
- Create test cases for the triangle program based on your equivalence classes.
Lab Experiments
For this task you will be testing a calculator application using failure (dirty) testing and error guessing. The application to be tested can be downloaded from the class website.
This application is a simple calculator which implements a number of standard calculator operations. Characters are regarded as invalid input. For this task you will make test cases to cover the provided mathematical functionality of the program. Consider all mathematical operators, invalid inputs, and orders of operation (BEDMAS). Record the results of your testing and identify and errors in the application you find.
Task 2 (50 marks)::(35 marks)
For this task you will be testing a command line triangle classification program. The application is available on the class website.
The triangle application reads in three space separated integers representing the length of each side of the triangle, and outputs either the type of triangle (scalene, isosceles, or equilateral) or gives an error message. Integers should be entered after the prompt:
triangle> a b c
For example triangle> 5 5 5 Should output Equilateral
A more detailed specification for the input and output of the program follows:
Input:
- Takes 3 positive integers
- Only accepts integers
- Three integers on the same line separated by a space character Command is executed by pressing enter.
Output:
- Prints out triangle type, one of scalene, equilateral, or isosceles ● Or an error message
