Branch coverage in Testing Fundamentals - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is branch coverage in software testing?

Branch coverage measures whether each possible branch (true/false decision) in the code has been executed at least once during testing.

beginner

Why is branch coverage important?

It helps find bugs in decision points by ensuring all branches of conditional statements are tested, improving test thoroughness.

intermediate

How does branch coverage differ from statement coverage?

Statement coverage checks if each line runs, but branch coverage checks if each decision path (true/false) runs, making it more detailed.

beginner

Example: If a code has an if-else statement, how many branches are there?

There are two branches: one for the 'if' condition being true, and one for it being false (the 'else').

intermediate

What does 100% branch coverage mean?

It means every possible branch in the code has been executed at least once during testing, covering all decision outcomes.

What does branch coverage measure in testing?

A Whether the code is free of syntax errors

B Whether each line of code is executed

C Whether the software meets user requirements

D Whether each decision branch (true/false) is executed

Branch coverage focuses on testing all possible paths of decisions, like true and false branches.

If an if statement has no else, how many branches does it have?

A Two

B One

C Three

D Zero

Even without an else, the if condition can be true or false, so there are two branches.

Which coverage is more detailed: statement coverage or branch coverage?

A Both are the same

B Statement coverage

C Branch coverage

D Neither

Branch coverage checks all decision paths, which is more detailed than just checking lines executed.

What does 100% branch coverage guarantee?

A All decision outcomes are tested

B All code lines are executed

C No bugs remain

D All user requirements are met

100% branch coverage means every true and false path in decisions has been tested.

Why might branch coverage miss some bugs?

A Because it only tests syntax

B Because it doesn't check data values inside branches

C Because it tests all user inputs

D Because it ignores decision points

Branch coverage ensures paths run but may miss bugs related to specific data values inside those paths.

Explain branch coverage and why it is useful in testing.

Think about how decisions in code create different paths to test.

Describe how you would achieve 100% branch coverage for a simple if-else statement.

Consider testing both outcomes of the condition.

Practice

1. What does branch coverage testing ensure in software testing?

easy

A. All possible paths of each decision point are tested

B. Only the main function is tested

C. All variables are initialized

D. The software runs faster

Solution

1. Step 1: Understand branch coverage concept

   Branch coverage means testing every decision point in the code, including both true and false outcomes.

2. Step 2: Match concept to options

   All possible paths of each decision point are tested correctly states that all possible paths of each decision point are tested, which is the essence of branch coverage.

3. Final Answer:

   All possible paths of each decision point are tested -> Option A

4. Quick Check:

   Branch coverage = all decision paths tested [OK]

Hint: Branch coverage tests both true and false paths [OK]

Common Mistakes:

• Confusing branch coverage with statement coverage
• Thinking it only tests main functions
• Assuming it improves speed

2. Which of the following is the correct way to write a branch coverage test condition in pseudocode?

easy

A. print('Test complete')

B. while x > 10 do A

C. for i in range(10): do A

D. if (x > 10) then do A else do B

Solution

1. Step 1: Identify branch decision structure

   Branch coverage requires a decision point with two or more paths, like an if-else condition.

2. Step 2: Check options for decision points

   if (x > 10) then do A else do B shows an if-else statement, which has two branches (true and false). Other options do not have decision branches.

3. Final Answer:

   if (x > 10) then do A else do B -> Option D

4. Quick Check:

   If-else = branch decision [OK]

Hint: Look for if-else to identify branches [OK]

Common Mistakes:

• Choosing loops as branch examples
• Ignoring else part of if-else
• Confusing print statements with branches

3. Consider the following code snippet:

if (a > 0) {
  if (b == 5) {
    print('Path 1');
  } else {
    print('Path 2');
  }
} else {
  print('Path 3');
}

How many test cases are needed for 100% branch coverage?

medium

A. 3

B. 4

C. 2

D. 5

Solution

1. Step 1: Identify decision points and branches

   There are two if statements: outer (a > 0) with true/false branches, inner (b == 5) with true/false branches.

2. Step 2: Count unique branches

   Outer if: 2 branches (true, false). Inner if (only if outer true): 2 branches. Total branches = 3 unique paths: Path 1, Path 2, Path 3.

3. Final Answer:

   3 -> Option A

4. Quick Check:

   Branches = 3 paths [OK]

Hint: Count all true/false branches in nested ifs [OK]

Common Mistakes:

• Counting only outer if branches
• Assuming each if adds 2 test cases independently
• Ignoring nested structure

4. You have this code:

if (x != 0) {
  print('Non-zero');
}

A test case with x = 0 is missing. What branch coverage issue does this cause?

medium

A. True branch not tested

B. False branch not tested

C. Syntax error in code

D. All branches covered

Solution

1. Step 1: Identify branches in the if condition

   The if condition has two branches: true (x != 0) and false (x == 0).

2. Step 2: Analyze test cases given

   Only test cases with x != 0 exist, so true branch is tested but false branch (x == 0) is missing.

3. Final Answer:

   False branch not tested -> Option B

4. Quick Check:

   Missing false branch test = coverage gap [OK]

Hint: Test both true and false conditions for full coverage [OK]

Common Mistakes:

• Assuming one test case covers all branches
• Confusing true and false branches
• Thinking missing test causes syntax error

5. Given this code:

if (score >= 90) {
  grade = 'A';
} else if (score >= 75) {
  grade = 'B';
} else {
  grade = 'C';
}

How many test cases are needed for 100% branch coverage?

hard

A. 2

B. 5

C. 3

D. 4

Solution

1. Step 1: Identify all decision points and branches

   There are two if conditions: first (score >= 90) with true/false branches, second (score >= 75) with true/false branches inside else.

2. Step 2: Count unique branches

   Branches: first if true (score>=90), first false + second true (75<=score<90), first false + second false (score<75). Total 3 test cases needed for 100% coverage.

3. Final Answer:

   3 -> Option C

4. Quick Check:

   if-else-if-else chain = 3 test cases [OK]

Hint: Count all true/false branches in if-else if-else chains [OK]

Common Mistakes:

• Counting only if statements, ignoring else
• Assuming 4 test cases are needed
• Missing nested else if branches