Definition of White Box Testing
White box testing is a software testing method that examines the internal workings of an application's code to ensure that it functions as expected. In other words, white box testing involves testing an application's internal structure, design, and implementation to identify potential issues or defects.
Importance of White Box Testing
White box testing is essential to software testing as it helps identify and eliminate defects in the application's code before it reaches the end users. This type of testing provides insight into the application's internal components' functionality, which can help optimize code performance and improve the software's overall quality.
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Types of White Box Testing
White box testing is a type of software testing that involves examining the internal workings of an application's code. This contrasts with black box testing, where testers cannot access the source code and test the application solely based on its external behavior. White box testing can be particularly effective for catching issues related to code errors, security vulnerabilities, and performance problems.
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Unit Testing: Unit testing involves testing individual units or components of an application's source code. The developers typically do this testing and aim to catch errors immediately. Unit testing can be done using testing frameworks like JUnit or NUnit.
Integration Testing: Integration testing involves testing how different units of an application's source code interact. This testing ensures that individual components of an application work correctly when integrated. Integration testing can be done manually or with tools like Selenium.
Execution Testing: Execution testing involves testing an application's performance in different conditions. This type of testing is used to determine how the application behaves when there is a high load on the system or a sudden increase in traffic.
Operation Testing: Operation testing involves testing an application's ability to operate in different environments. This type of testing checks that the application functions correctly in other operating systems and browsers.
Mutation Testing: Mutation testing involves modifying an application's source code to see if the tests that have been written can detect these modifications. This type of testing is used to ensure that tests are effective in detecting code changes.
Top-Down Approach: In this approach, testing begins at the highest level of an application's architecture and proceeds to lower levels. This approach ensures that the application's overall functionality is working correctly.
Bottom-Up Approach: In this approach, testing begins at the lowest level of an application's architecture and proceeds to higher levels. This approach is used to ensure that individual components of the application are working correctly.
Statement Coverage: Statement coverage involves measuring the percentage of code statements executed during testing. This type of testing ensures that all code statements are being tested.
Branch Coverage: Branch coverage measures the percentage of code branches executed during testing. This type of testing ensures that all possible paths through the code are being tested.
Path Coverage: Path coverage measures the percentage of code paths executed during testing. This type of testing ensures that all possible combinations of code paths are being tested.
Hybrid Approach: In this approach, testing combines the top-down and bottom-up approaches to achieve comprehensive test coverage. This approach is used to ensure that the entire application is tested thoroughly.
Examples of White Box Testing
Unit Testing
Unit testing is white box testing that tests individual units or components of an application's source code. Developers typically perform this type of testing to ensure that each separate unit or code member is functioning correctly.
Example code for a unit test using the Python unit test framework:
import unittest
def add_numbers(a, b):
return a + b
class TestAddition(unittest.TestCase):
def test_add_positive_numbers(self):
self.assertEqual(add_numbers(2, 3), 5)
def test_add_negative_numbers(self):
self.assertEqual(add_numbers(-2, -3), -5)
def test_add_mixed_numbers(self):
self.assertEqual(add_numbers(2, -3), -1)
if __name__ == '__main__':
unittest.main()
In this example, we define a function add_nufor this function using the unit test.TestCase class. Each test case is defined as a metmbers that takes two parameters and returns their sum. We then define a set of test cases Inhod that calls the add_numbers function with specific inputs and checks the output against an expected value using the assertEqual method.
Integration Testing
Is white box testing that tests the interactions between different components or units of an application's source code. Developers typically perform this type of testing to ensure that the other parts or branches of the code work together correctly.
Example code for an integration test using the Python unit test framework:
import unittest
class Calculator:
def add(self, a, b):
return a + b
class TestCalculator(unittest.TestCase):
def setUp(self):
self.calculator = Calculator()
def test_add_positive_numbers(self):
self.assertEqual(self.calculator.add(2, 3), 5)
def test_add_negative_numbers(self):
self.assertEqual(self.calculator.add(-2, -3), -5)
def test_add_mixed_numbers(self):
self.assertEqual(self.calculator.add(2, -3), -1)
if __name__ == '__main__':
unittest.main()In this example, we define a class Calculator that has a method add that takes two parameters and returns their sum. We then define a set of test cases for this class using the unittest.TestCase class. Each test case is defined as a method that creates an instance of the Calculator class, calls the add method with specific inputs, and checks the output against an expected value using the assertEqual method.
System Testing
System testing is white box testing that focuses on testing the entire system or application, including all its components or units, to ensure that it functions correctly. Testers or quality assurance professionals typically perform this type of testing.
Example code for a system test using the Python unit test framework:
import unittest
from selenium import webdriver
class TestGoogle(unittest.TestCase):
def setUp(self):
self.driver = webdriver.Chrome()
self.driver.maximize_window()
def test_search_for_python(self):
self.driver.get("https://www.google.com/")
search_box = self.driver.find_element_by_name("q")
search_box.send_keys("Python")
search_box.submit()
results = self.driver.find_elements_by_css_selector("h3.LC20lb")
self.assertGreater(len(results), 0)
def tearDown(self):
self.driver.quit()
if __name__ == '__main__':
unittest.main()In this example, we define a set of system tests using the unittest.TestCase class and the Selenium web driver for automated.