Boundary value analysis in Testing Fundamentals - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is Boundary Value Analysis (BVA) in software testing?

Boundary Value Analysis is a testing technique that focuses on testing the values at the edges or boundaries of input domains, where errors are most likely to occur.

beginner

Why do testers focus on boundary values rather than just any random values?

Because errors often happen at the edges of input ranges, testing boundary values helps find defects that might be missed by testing only typical or random values.

intermediate

List the typical boundary values tested in Boundary Value Analysis.

The typical boundary values are: the minimum value, just below the minimum, just above the minimum, the maximum value, just below the maximum, and just above the maximum.

intermediate

How is Boundary Value Analysis related to Equivalence Partitioning?

Equivalence Partitioning divides input data into groups where test cases are expected to behave similarly, while Boundary Value Analysis tests the edges of these groups to catch errors at the limits.

beginner

Give a simple example of Boundary Value Analysis for an input field that accepts ages from 18 to 60.

Test values would include: 17 (just below min), 18 (min), 19 (just above min), 59 (just below max), 60 (max), and 61 (just above max).

What is the main focus of Boundary Value Analysis?

A Testing only valid inputs

B Testing random inputs

C Testing values at the edges of input ranges

D Testing only invalid inputs

Boundary Value Analysis focuses on testing values at the edges or boundaries of input ranges where errors are most likely.

Which of the following is NOT a typical boundary value to test for an input range?

A Middle value

B Maximum value

C Minimum value

D Just above maximum value

Boundary Value Analysis tests edges like minimum, maximum, and values just outside these boundaries, not the middle value.

If an input accepts values from 1 to 100, which value should NOT be tested in Boundary Value Analysis?

A 101

B 1

C 0

D 50

50 is a middle value, not a boundary value. BVA focuses on edges like 1, 0 (just below min), 100, and 101 (just above max).

How does Boundary Value Analysis help improve test effectiveness?

A By focusing on the most error-prone input values at boundaries

B By ignoring edge cases

C By testing only valid inputs

D By reducing the number of test cases to only one

BVA improves effectiveness by focusing on boundary inputs where errors are more likely to occur.

Which testing technique is often combined with Boundary Value Analysis?

A Performance Testing

B Equivalence Partitioning

C Security Testing

D Usability Testing

Equivalence Partitioning groups inputs, and Boundary Value Analysis tests the edges of those groups.

Explain Boundary Value Analysis and why it is important in software testing.

Think about why testing just the middle values might miss bugs.

Describe how you would select test cases using Boundary Value Analysis for an input accepting numbers from 10 to 50.

Remember to test just outside the allowed range too.

Practice

1. What is the main goal of Boundary Value Analysis in software testing?

easy

A. To test the software's user interface design

B. To test inputs at the edges of input ranges

C. To test the software's performance under load

D. To test only the middle values of input ranges

Solution

1. Step 1: Understand boundary value analysis purpose

   Boundary value analysis focuses on testing the edges or limits of input ranges where errors often occur.

2. Step 2: Compare options with definition

   Only To test inputs at the edges of input ranges correctly describes testing inputs at the edges of input ranges.

3. Final Answer:

   To test inputs at the edges of input ranges -> Option B

4. Quick Check:

   Boundary value analysis = test edges [OK]

Hint: Focus on testing minimum and maximum input values [OK]

Common Mistakes:

• Confusing boundary testing with performance testing
• Testing only middle values instead of edges
• Ignoring values just outside the boundaries

2. Which of the following is the correct set of test inputs for boundary value analysis of an input field that accepts values from 1 to 10?

easy

A. 1, 5, 10

B. 0, 5, 10

C. 2, 5, 9

D. 0, 1, 10, 11

Solution

1. Step 1: Identify boundary values for range 1 to 10

   Boundaries are minimum (1) and maximum (10). Values just outside are 0 and 11.

2. Step 2: Check options for boundary and just outside values

   0, 1, 10, 11 includes 0 (just below min), 1 (min), 10 (max), and 11 (just above max), which is correct for boundary testing.

3. Final Answer:

   0, 1, 10, 11 -> Option D

4. Quick Check:

   Include min, max, and just outside values [OK]

Hint: Always test min, max, and values just outside boundaries [OK]

Common Mistakes:

• Testing only valid values inside the range
• Ignoring values just outside the boundaries
• Choosing random values without boundary focus

3. Consider a function that accepts an integer input from 5 to 15 inclusive. Which of the following test inputs is NOT a valid boundary value test case?

medium

A. 10

B. 5

C. 4

D. 15

Solution

1. Step 1: Identify boundary values and just outside values

   Boundaries are 5 (min) and 15 (max). Just outside are 4 and 16.

2. Step 2: Check which input is not a boundary or just outside value

   Inputs 4, 5, and 15 are boundary or just outside values. 10 is a normal middle value, not a boundary test case.

3. Final Answer:

   10 -> Option A

4. Quick Check:

   Boundary tests exclude middle values like 10 [OK]

Hint: Exclude middle values; test edges and just outside only [OK]

Common Mistakes:

• Including middle values as boundary tests
• Ignoring values just outside boundaries
• Confusing valid inputs with boundary inputs

4. A tester wrote these boundary test inputs for a field accepting values 10 to 20: 9, 10, 20, 21. The test failed for input 21. What is the most likely reason?

medium

A. The software has a bug accepting 21

B. The test inputs are incorrect; 21 should be accepted

C. 21 is outside the valid input range and should fail

D. Boundary value analysis does not require testing outside the range

Solution

1. Step 1: Understand boundary test inputs and expected behavior

   Inputs 9 and 21 are just outside the valid range 10 to 20, so failure on 21 is expected.

2. Step 2: Analyze test failure reason

   Since 21 is invalid input, failure means software correctly rejects it. So test failure is expected, not a bug.

3. Final Answer:

   21 is outside the valid input range and should fail -> Option C

4. Quick Check:

   Outside boundary inputs should cause failure [OK]

Hint: Expect failure for inputs just outside boundaries [OK]

Common Mistakes:

• Thinking failure on invalid input is a bug
• Not testing values just outside boundaries
• Assuming all test inputs must pass

5. A form accepts age input from 18 to 60 inclusive. Using boundary value analysis, which set of test inputs covers all necessary boundary cases including just outside values?

hard

A. 17, 18, 60, 61

B. 18, 30, 60

C. 16, 18, 59, 61

D. 18, 19, 59, 60

Solution

1. Step 1: Identify boundary and just outside values for age 18 to 60

   Boundaries are 18 (min) and 60 (max). Just outside are 17 (below min) and 61 (above max).

2. Step 2: Check which option includes all boundaries and just outside values

   17, 18, 60, 61 includes 17, 18, 60, and 61, covering all required boundary and just outside values.

3. Final Answer:

   17, 18, 60, 61 -> Option A

4. Quick Check:

   Test min, max, and just outside values for full coverage [OK]

Hint: Always include min, max, and one value outside each boundary [OK]

Common Mistakes:

• Missing just outside boundary values
• Testing only valid inputs inside range
• Confusing boundary values with random inputs