📏Testing

Learn basics of testing programs.

When a computer system is being developed, it goes through various testing stages in the following order:

Module testing

To make sure that specific subroutines work as they were intended to do so.

Program testing

To make sure each program in the system works correctly

System testing

To make sure the whole system works as expected and meets the original specifications.

Purpose of Testing

Testing is vital for finding errors in certain parts of a computer system. Finding and fixing these errors is very important for improving the user experience and also helps reduce chances of cybersecurity incidents.

Testing is not done to prove that the program "works most of the times", although ensuring functionality and reliability is important in testing, the primary goal is to uncover defects and vulnerabilities in the system. A good test should show up an error.

In order to test, you don't necessarily need to know how the program works, you just need to know what it's supposed to do.

Designing a Test Plan

Test data has to be carefully selected. It should include normal (typical) data, boundary data and erroneous data.

A test plan needs to have the following columns

Hand-tracing Algorithms

Hand-tracing an algorithm can help us find how an algorithm works and why it is not working properly. A trace table is used to write down the contents of each variable as it changes during execution. If the program contains a loop, a helpful technique is to put the loop condition as the first column in the trace table, even if other variables have been defined before it.

Sample trace table

n = 5
FOR count = 1 to n
	a = n - count
	b = 3 * a + count
ENDFOR
OUTPUT b

example of a trace table