Equivalence partitioning and boundary value analysis in Software Engineering - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define an equivalence partition for ages between 18 and 60.

Software Engineering

def is_valid_age(age):
    return [1]

Drag options to blanks, or click blank then click option'

A18 <= age <= 60

Bage < 18 or age > 60

Cage > 18 and age < 60

Dage == 18 or age == 60

Attempts:

3 left

💡 Hint

Common Mistakes

Using < or > instead of <= or >=, which excludes boundary values.

Using 'or' instead of 'and' in the condition.

The correct equivalence partition for valid ages includes all ages from 18 to 60 inclusive, so the condition 18 <= age <= 60 correctly checks this range.

2fill in blank

medium

Complete the code to test the lower boundary value for a password length of at least 8 characters.

Software Engineering

def is_valid_password(password):
    return len(password) [1] 8

Drag options to blanks, or click blank then click option'

A>

B<

C>=

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' which excludes passwords of length exactly 8.

Using '<' or '<=' which are incorrect for minimum length checks.

The password length should be at least 8 characters, so the correct operator is >= to include passwords with length exactly 8.

3fill in blank

hard

Fix the error in the boundary value check for input between 1 and 100 inclusive.

Software Engineering

def is_in_range(value):
    return value [1] 1 and value [2] 100

Drag options to blanks, or click blank then click option'

A>=

B<=

C>

D<

Attempts:

3 left

💡 Hint

Common Mistakes

Using '>' or '<' which exclude boundary values.

Mixing up the operators for lower and upper bounds.

To check if a value is between 1 and 100 inclusive, use >= 1 and <= 100. This includes the boundary values 1 and 100.

4fill in blank

hard

Fill both blanks to create a test condition that partitions input into valid and invalid age groups using equivalence partitioning.

Software Engineering

def age_group(age):
    if age [1] 17:
        return 'invalid'
    elif age [2] 18:
        return 'valid'

Drag options to blanks, or click blank then click option'

A<=

B>=

C<

D>

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' instead of '<=' excludes age 17 from invalid group.

Using '>' instead of '>=' excludes age 18 from valid group.

To separate invalid ages as 17 or less, use <= 17. To mark valid ages as 18 or more, use >= 18.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension that maps test inputs to their validity using boundary value analysis.

Software Engineering

test_results = {input_value: (input_value [1] 0 and input_value [2] 100) for input_value in [[3]]}

Drag options to blanks, or click blank then click option'

A>=

B<=

C50, 0, 100

D10, -1, 101

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<' or '>' which exclude boundary values.

Choosing test inputs outside the valid range.

The dictionary comprehension checks if each input_value is between 0 and 100 inclusive using >= 0 and <= 100. The test inputs include 50, 0, and 100 to cover boundary and typical 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