White-box testing techniques in Software Engineering - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is white-box testing?

White-box testing is a software testing method where the tester has full knowledge of the internal structure, design, and implementation of the software being tested.

intermediate

Name a common white-box testing technique that checks every possible path through the code.

Path testing is a white-box technique that aims to execute all possible paths in the program to find errors in the logic or flow.

beginner

What does statement coverage measure in white-box testing?

Statement coverage measures the percentage of executable statements in the code that have been executed by the test cases.

intermediate

Explain branch coverage in white-box testing.

Branch coverage ensures that each possible branch (true/false) from every decision point in the code is executed at least once during testing.

beginner

Why is white-box testing important in software development?

White-box testing helps find hidden errors, improves code quality, verifies internal operations, and ensures that all parts of the code work as expected.

Which of the following is a white-box testing technique?

A Statement coverage

B Usability testing

C Black-box testing

D Beta testing

Statement coverage is a white-box testing technique that measures how many statements are executed.

What does branch coverage test in white-box testing?

A Each decision point's true and false outcomes

B All possible paths through the code

C User interface elements

D Performance under load

Branch coverage ensures that both true and false branches of each decision are tested.

Which is NOT a goal of white-box testing?

A Check internal code logic

B Test software without knowing code

C Find hidden errors

D Improve code quality

Testing without knowing the code is black-box testing, not white-box testing.

Path testing aims to:

A Test only the user interface

B Test software performance

C Check database connections

D Execute all possible paths in the code

Path testing tries to cover every possible route through the program's code.

Which coverage type measures the percentage of executed statements?

A Branch coverage

B Path coverage

C Statement coverage

D Function coverage

Statement coverage measures how many statements have been run during testing.

Describe the main white-box testing techniques and what each aims to achieve.

Think about how testers check code lines, decisions, and paths.

Explain why white-box testing is important and how it differs from black-box testing.

Consider what testers know about the software in each method.

Practice

1. Which of the following best describes white-box testing?

easy

A. Testing that examines the internal structure of the code

B. Testing that focuses only on user interface behavior

C. Testing done without knowledge of the code

D. Testing that only checks software performance

Solution

1. Step 1: Understand white-box testing definition

   White-box testing involves looking inside the code to test its logic and structure.

2. Step 2: Compare options to definition

   Testing that examines the internal structure of the code matches this definition exactly, while others focus on external or unrelated aspects.

3. Final Answer:

   Testing that examines the internal structure of the code -> Option A

4. Quick Check:

   White-box testing = internal code check [OK]

Hint: White-box tests look inside the code, not just outside [OK]

Common Mistakes:

• Confusing white-box with black-box testing
• Thinking white-box tests only check UI
• Assuming white-box ignores code structure

2. Which syntax correctly represents a common white-box testing technique?

easy

A. User acceptance testing

B. Branch coverage

C. Load testing

D. Smoke testing

Solution

1. Step 1: Identify white-box testing techniques

   Common white-box techniques include statement, branch, path, and condition coverage.

2. Step 2: Match options to white-box techniques

   Only branch coverage is a white-box technique; others are types of testing but not white-box.

3. Final Answer:

   Branch coverage -> Option B

4. Quick Check:

   Branch coverage = white-box technique [OK]

Hint: Branch coverage is a classic white-box technique [OK]

Common Mistakes:

• Confusing black-box tests with white-box
• Choosing performance or acceptance tests
• Ignoring coverage-based techniques

3. Consider the following code snippet:

if (x > 0) {
  print("Positive");
} else {
  print("Non-positive");
}

Which white-box testing technique ensures both if and else branches are tested?

medium

A. Statement coverage

B. Path coverage

C. Branch coverage

D. Condition coverage

Solution

1. Step 1: Understand the code branches

   The code has two branches: one for x > 0 true, one for false.

2. Step 2: Identify technique testing all branches

   Branch coverage requires testing each branch (if and else) at least once.

3. Final Answer:

   Branch coverage -> Option C

4. Quick Check:

   Branch coverage = test all branches [OK]

Hint: Branch coverage tests all decision paths [OK]

Common Mistakes:

• Confusing statement coverage with branch coverage
• Thinking path coverage is simpler
• Ignoring else branch testing

4. A tester wrote this code to check condition coverage:

if (a > 10 && b < 5) {
  print("Valid");
}

Which mistake would cause incomplete condition coverage?

medium

A. Testing only when both conditions are true

B. Testing when a is 5 and b is 3

C. Testing when a is 15 and b is 6

D. Testing when a is 20 and b is 2

Solution

1. Step 1: Understand condition coverage

   Condition coverage requires testing each condition (a > 10 and b < 5) as true and false separately.

2. Step 2: Analyze testing only both true

   If only tested when both are true, false cases for each condition are not tested, so coverage is incomplete.

3. Final Answer:

   Testing only when both conditions are true -> Option A

4. Quick Check:

   Condition coverage = test each condition true/false [OK]

Hint: Test each condition true and false separately [OK]

Common Mistakes:

• Testing only combined true cases
• Ignoring false condition tests
• Assuming one test covers all conditions

5. You want to ensure every possible route through this code is tested:

if (x > 0) {
  if (y > 0) {
    print("Both positive");
  } else {
    print("x positive, y non-positive");
  }
} else {
  print("x non-positive");
}

Which white-box testing technique best guarantees this?

hard

A. Condition coverage

B. Statement coverage

C. Branch coverage

D. Path coverage

Solution

1. Step 1: Identify all possible paths

   There are three paths: both x and y positive, x positive and y non-positive, x non-positive.

2. Step 2: Understand path coverage

   Path coverage requires testing every possible route through the code, covering all combinations of decisions.

3. Step 3: Compare with other techniques

   Statement and branch coverage do not guarantee all paths; condition coverage tests conditions but not all paths.

4. Final Answer:

   Path coverage -> Option D

5. Quick Check:

   Path coverage = test all routes [OK]

Hint: Path coverage tests every possible route through code [OK]

Common Mistakes:

• Confusing branch with path coverage
• Assuming statement coverage is enough
• Ignoring nested conditions