Equivalence partitioning and boundary value analysis in Software Engineering - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding Equivalence Partitioning

Which of the following best describes the purpose of equivalence partitioning in software testing?

A To test only the smallest and largest values of input data

B To divide input data into groups that are expected to be treated the same by the software

C To check the software's response to invalid inputs only

D To write test cases that cover every possible input value

💡 Hint

Think about grouping inputs that behave similarly to reduce test cases.

Equivalence partitioning divides inputs into groups where all values in a group are expected to be handled the same way, reducing the number of test cases needed.

🔍 Analysis

intermediate

Boundary Value Analysis Output

Consider a function that accepts an integer input between 1 and 10 inclusive. Which test input value is a boundary value?

Software Engineering

def test_input(value):
    if 1 <= value <= 10:
        return "Valid"
    else:
        return "Invalid"

A 1

B 11

C 5

D 0

💡 Hint

Boundary values are at the edges of valid input ranges.

Boundary values are the smallest and largest valid inputs, here 1 and 10. Among options, 1 is a boundary value.

❓ assertion

advanced

Assertion for Boundary Value Test

Which assertion correctly tests that a function calculate_discount returns 0% discount for purchase amounts less than $100?

Software Engineering

def calculate_discount(amount):
    if amount >= 100:
        return 10
    else:
        return 0

A assert calculate_discount(101) == 0

B assert calculate_discount(100) == 0

C assert calculate_discount(99) == 0

D assert calculate_discount(50) == 10

💡 Hint

Check the discount for just below the boundary value.

For amounts less than 100, discount is 0. Testing with 99 checks this boundary condition correctly.

🔍 Analysis

advanced

Debugging Equivalence Partitioning Test Cases

Given the following test cases for a function accepting ages 18 to 60 inclusive, which test case is incorrectly chosen based on equivalence partitioning?

Software Engineering

test_cases = [17, 18, 30, 60, 61]

A 61 - valid partition boundary

B 18 - valid partition boundary

C 30 - valid partition middle

D 17 - invalid partition

💡 Hint

Check if 61 belongs to any valid or invalid partition.

61 is outside the valid range and belongs to the invalid partition, but it is not a boundary value for invalid inputs since 61 is just above 60. The boundary invalid value should be 61, but 61 is not a boundary value for equivalence partitions here.

❓ framework

expert

Designing Test Cases Using Both Techniques

You need to design test cases for a login form that accepts passwords between 8 and 12 characters. Which set of test inputs best combines equivalence partitioning and boundary value analysis?

A [6, 7, 13, 14, 15]

B [1, 5, 8, 12, 20]

C [8, 9, 10, 11, 12]

D [7, 8, 10, 12, 13]

💡 Hint

Include values just outside and inside the valid range.

Option D includes values just below (7), at the lower boundary (8), a middle valid value (10), at the upper boundary (12), and just above (13), covering both equivalence partitions and boundary values.

Practice

1. Which of the following best describes equivalence partitioning in software testing?

easy

A. Running all possible input combinations exhaustively

B. Testing only the maximum input value of a range

C. Checking the software's response to invalid inputs only

D. Dividing input data into groups where test cases represent each group

Solution

1. Step 1: Understand equivalence partitioning concept

   Equivalence partitioning divides inputs into groups where all inputs in a group are expected to behave similarly.

2. Step 2: Match description to options

   Dividing input data into groups where test cases represent each group correctly states this grouping approach. Other options describe different testing ideas.

3. Final Answer:

   Dividing input data into groups where test cases represent each group -> Option D

4. Quick Check:

   Equivalence partitioning = Group inputs [OK]

Hint: Group inputs by behavior to reduce tests [OK]

Common Mistakes:

• Confusing equivalence partitioning with boundary value analysis
• Thinking it tests only invalid inputs
• Assuming it requires exhaustive testing

2. Which of the following is the correct boundary value test inputs for a field accepting integers from 1 to 10 inclusive?

easy

A. 1, 2, 9, 10

B. 1, 5, 10

C. 0, 1, 10, 11

D. 0, 5, 10

Solution

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

   Boundaries are the edges: minimum (1), maximum (10), and just outside edges (0 and 11).

2. Step 2: Check options for correct boundary inputs

   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 C

4. Quick Check:

   Boundary values = edges and just outside [OK]

Hint: Test edges plus one inside and outside values [OK]

Common Mistakes:

• Testing only valid inputs ignoring just outside boundaries
• Choosing random middle values instead of edges
• Missing one side of the boundary

3. Consider a function that accepts an integer input from 1 to 5 inclusive. Which set of test inputs covers both equivalence partitioning and boundary value analysis?

medium

A. [0, 1, 3, 5, 6]

B. [1, 2, 3, 4, 5]

C. [1, 5]

D. [2, 3, 4]

Solution

1. Step 1: Identify equivalence partitions and boundaries

   Partitions: invalid below (<=0), valid (1-5), invalid above (>=6). Boundaries: 1 and 5 plus just outside 0 and 6.

2. Step 2: Check which option covers all partitions and boundaries

   [0, 1, 3, 5, 6] includes 0 (below), 1 (min boundary), 3 (valid middle), 5 (max boundary), and 6 (above), covering partitions and boundaries.

3. Final Answer:

   [0, 1, 3, 5, 6] -> Option A

4. Quick Check:

   Partitions + boundaries = test edges and groups [OK]

Hint: Include invalid, valid, and boundary values [OK]

Common Mistakes:

• Ignoring invalid partitions
• Testing only boundaries without middle values
• Choosing only valid inputs

4. A tester wrote these test inputs for a field accepting values 10 to 20 inclusive: [9, 10, 15, 20, 21]. The test failed to catch a bug at input 21. What is the likely mistake?

medium

A. They only tested valid inputs and ignored invalid ones

B. They did not include invalid inputs below 10

C. They missed testing the exact boundary values

D. They did not test the boundary just above the max value correctly

Solution

1. Step 1: Analyze test inputs and bug location

   Inputs include 9 (below min), 10 (min), 15 (middle), 20 (max), and 21 (just above max). Bug at 21 means boundary above max was tested.

2. Step 2: Identify mistake causing bug miss

   Since bug was missed at 21, likely the test did not properly check or handle the boundary just above max, possibly due to incorrect validation or test setup.

3. Final Answer:

   They only tested valid inputs and ignored invalid ones -> Option A

4. Quick Check:

   Boundary above max must be tested carefully [OK]

Hint: Check boundaries just outside valid range carefully [OK]

Common Mistakes:

• Assuming testing 21 is enough without checking handling
• Ignoring off-by-one errors at boundaries
• Not validating test setup correctness

5. You have a form field that accepts ages from 18 to 60 inclusive. Using equivalence partitioning and boundary value analysis, which of the following test sets is the most effective to detect input errors?

hard

A. [18, 19, 20, 59, 60]

B. [17, 18, 30, 60, 61]

C. [18, 30, 60]

D. [16, 18, 60, 62]

Solution

1. Step 1: Define equivalence partitions and boundaries for age 18-60

   Partitions: invalid below 18, valid 18-60, invalid above 60. Boundaries: 18 (min), 60 (max), and just outside 17 and 61.

2. Step 2: Evaluate options for coverage

   [17, 18, 30, 60, 61] includes 17 (below min), 18 (min), 30 (valid middle), 60 (max), and 61 (above max), covering all partitions and boundaries effectively.

3. Final Answer:

   [17, 18, 30, 60, 61] -> Option B

4. Quick Check:

   Test invalid, valid, and boundary values for best coverage [OK]

Hint: Test just below, at, inside, and just above boundaries [OK]

Common Mistakes:

• Ignoring invalid partitions
• Testing only valid inputs
• Missing boundary values just outside range