White Box Testing

Before discussing the details of white box testing, it's important to recall that manual testing is a critical process in software development that helps ensure that software application meets the specified requirements and functions correctly under different conditions.

It's necessary to remind you that there are three types of manual testing:

📄️ White Box Testing

White Box Testing is a software testing technique that focuses on testing the internal workings of a software application, including its code, structure, and design. In this type of testing, testers have access to the application's source code and use various testing methods to ensure that the application functions as intended and meets the required quality standards.

📄️ Grey Box Testing

This tutorial provides an introduction to Grey Box Testing, which is a software testing technique that combines the benefits of Black Box and White Box Testing. It explains the concept of Grey Box Testing, its benefits, techniques used, and limitations.

📄️ Black Box Testing

This tutorial provides an overview of different techniques used in black box testing, including equivalence partitioning, boundary value analysis, decision table testing, state transition testing, error guessing, and comparison testing. Each technique is explained in detail with examples and graphical representations.

White box testing is a software testing technique in which the tester has knowledge of the internal workings of the software application being tested. In white box testing, the tester has access to the source code, the design documents, and the architecture of the software application, and uses this information to design test cases and perform tests.

What is the White Box Testing?

White box testing is a software testing technique in which the tester has knowledge of the internal workings of the software application being tested.

The primary goal of white box testing is to verify the correctness and efficiency of the code, and to ensure that the software application meets the specified requirements and functions correctly under different conditions. White box testing can help identify defects, errors, and other issues in the code, and can help improve the quality and reliability of the software application.

Note

White box testing is also known as Clear Box Testing, Glass Box Testing, or Structural Testing.
It is different from black box testing,

Type of White Box Testing

There are several types of white box testing techniques used in software testing. Some of the most commonly used types of white box testing:

Statement Coverage
Branch Coverage
Condition Coverage
Path Coverage
Loop Testing

1. Statement Coverage

This technique aims to test each statement of the code at least once. The goal is to ensure that all statements are executed and that there are no unreachable or dead code segments.

Example- Consider the following code snippet:

if (a > b) {
    c = a + b;
}
else {
    c = a - b;
}

For statement coverage, we would create test cases to ensure that each statement is executed at least once. For example, we could create two test cases:

Test case 1: a=5, b=3
Test case 2: a=3, b=5

Test case 1 would execute the first statement (since a > b is true), while test case 2 would execute the second statement (since a > b is false).

2. Branch Coverage

This technique aims to test each decision point in the code. The goal is to ensure that all possible paths through the code are tested, and that no logical decisions are overlooked.

Example Consider the following code snippet:

if (a > b) {
    c = a + b;
}
else {
    c = a - b;
}

For branch coverage, we would create test cases to ensure that each possible branch is executed. For example, we could create three test cases:

Test case 1: a=5, b=3
Test case 2: a=3, b=5
Test case 3: a=3, b=3

Test case 1 would execute the "if" branch, test case 2 would execute the "else" branch, and test case 3 would execute both branches.

3. Condition Coverage

This technique aims to test each logical condition within the code. The goal is to ensure that all possible combinations of logical conditions are tested.

What is logical condition?

A logical condition is a boolean expression that evaluates to either true or false. Here's an example of a logical condition:

if (age >= 18 && age <= 60) {
  // do something
}

In this example, the logical condition is (age >= 18 && age <= 60). It checks if the age variable is greater than or equal to 18 and less than or equal to 60.

Consider the following code snippet:

if ((a > b) && (c > d)) {
    e = a + b + c + d;
}
else {
    e = a - b - c - d;
}

For condition coverage, we would create test cases to ensure that each possible combination of conditions is tested. For example, we could create four test cases:

Test case 1: a=5, b=3, c=4, d=2
Test case 2: a=3, b=5, c=4, d=2
Test case 3: a=5, b=3, c=2, d=4
Test case 4: a=3, b=5, c=2, d=4

Test case 1 would execute the "if" branch (since both conditions are true), test case 2 and test case 3 would execute the "else" branch (since only one condition is true), and test case 4 would execute both branches (since both conditions are false).

4. Path Coverage:

This technique aims to test every possible path through the code. The goal is to ensure that all possible combinations of statements, decisions, and conditions are executed.

Consider the following code snippet:

if (a > b) {
    c = a + b;
}
else {
    c = a - b;
}
d = c * 2;

For path coverage, we would create test cases to ensure that each possible path through the code is executed. For example, we could create four test cases:

Test case 1: a=5, b=3
Test case 2: a=3, b=5
Test case 3: a=5, b=5
Test case 4: a=3, b=3

Test case 1 would execute the first path (if branch only), test case 2 would execute the second path (else branch only), test case 3 would execute both paths (if and else branches), and test case 4 would execute the single path through the code.

5. Loop Testing

This technique aims to test the loops in the code. The goal is to ensure that the code executes correctly for different iterations of the loop.

Consider the following code snippet:

for (i = 0; i < n; i++) {
    sum += a[i];
}

For loop testing, we would create test cases to ensure that the code executes correctly for different iterations of the loop. For example, we could create two test cases:

Test case 1: n=3, a=3
Test case 2: n=0, a=

Test case 1 would execute the loop three times (for i=0, i=1, and i=2), while test case 2 would not execute the loop at all (since n=0).

How to perform?

White box testing can be performed manually or with the help of automated testing tools. Testers can use different types of white box testing techniques, such as statement coverage, branch coverage, condition coverage, path coverage, and loop testing, to ensure comprehensive testing coverage of the software application.