Why data-driven tests increase coverage in Selenium Python - Test Your Understanding

Practice - 5 Tasks

1fill in blank

easy

Complete the code to run the test with multiple data inputs.

Selenium Python

for data in [1]:
    result = process(data)
    assert result == expected

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

Aprocess_data

Binput_data

Cdata_list

Dtest_data

Attempts:

3 left

💡 Hint

Common Mistakes

Using a single data item instead of a collection.

Using an undefined variable name.

The variable 'test_data' holds the multiple inputs for the data-driven test loop.

2fill in blank

medium

Complete the code to assert the expected output for each input.

Selenium Python

assert [1] == expected_output

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

Aoutput

Bresult

Cinput_value

Ddata

Attempts:

3 left

💡 Hint

Common Mistakes

Asserting the input instead of the output.

Using a variable that is not defined.

The variable 'result' holds the actual output to compare with the expected output.

3fill in blank

hard

Fix the error in the test function to correctly use data-driven testing.

Selenium Python

def test_function():
    for item in [1]:
        output = process(item)
        assert output == expected

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

Atest_cases

Btest_case

Ctestcase

Dtestcase_list

Attempts:

3 left

💡 Hint

Common Mistakes

Using a singular variable name that is not iterable.

Using an undefined variable.

The variable 'test_cases' correctly refers to the collection of inputs for the loop.

4fill in blank

hard

Fill both blanks to create a data-driven test that iterates and asserts correctly.

Selenium Python

for [1] in test_data:
    result = process([2])
    assert result == expected

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

Aitem

Bdata

Cinput

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names for loop and function input.

Using a variable not defined in the loop.

The loop variable 'item' is used both to iterate and as input to the process function.

5fill in blank

hard

Fill all three blanks to build a data-driven test with a descriptive assertion message.

Selenium Python

for [1] in test_inputs:
    output = process([2])
    assert output == expected, f"Failed for input: [3]"

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

Atest_input

Dinput_value

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names causing confusion.

Leaving the assertion message without the input variable.

Using 'test_input' consistently for the loop variable, function input, and message shows clear data flow.

Practice

1. Why do data-driven tests increase test coverage in Selenium Python?

easy

A. Because they skip validation steps

B. Because they reduce the number of test cases to one

C. Because they only test the UI layout

D. Because they run the same test steps with many different inputs

Solution

1. Step 1: Understand data-driven testing concept

   Data-driven tests repeat the same test steps but use different input data sets.

2. Step 2: Connect data variation to coverage

   Using many inputs helps test more scenarios, increasing coverage and finding more bugs.

3. Final Answer:

   Because they run the same test steps with many different inputs -> Option D

4. Quick Check:

   Data-driven tests = many inputs = more coverage [OK]

Hint: More inputs mean more scenarios tested [OK]

Common Mistakes:

• Thinking data-driven tests reduce test cases
• Confusing UI layout testing with data-driven testing
• Believing data-driven tests skip validations

2. Which of the following is the correct way to pass multiple data sets to a Selenium Python test using pytest parameterization?

easy

A. @pytest.parametrization('input', [1, 2, 3])

B. @pytest.parametrize('input', (1, 2, 3))

C. @pytest.mark.parametrize('input', [1, 2, 3])

D. @pytest.mark.parametrized('input', [1, 2, 3])

Solution

1. Step 1: Recall pytest parameterization syntax

   The correct decorator is @pytest.mark.parametrize with 'param' and list of values.

2. Step 2: Check each option syntax

   Only @pytest.mark.parametrize('input', [1, 2, 3]) uses correct spelling and syntax: @pytest.mark.parametrize('input', [1, 2, 3]).

3. Final Answer:

   @pytest.mark.parametrize('input', [1, 2, 3]) -> Option C

4. Quick Check:

   Correct pytest decorator = @pytest.mark.parametrize [OK]

Hint: Remember exact decorator spelling: parametrize with 'z' [OK]

Common Mistakes:

• Misspelling 'parametrize' as 'parametrize' or 'parametrized'
• Using parentheses instead of brackets for data list
• Confusing 'param' and 'parametrize'

3. Given this pytest data-driven test snippet, what will be the output if the test fails for input 3?

import pytest

@pytest.mark.parametrize('num', [1, 2, 3])
def test_is_even(num):
    assert num % 2 == 0

medium

A. Test fails only for input 3

B. Test fails for inputs 1 and 3

C. Test passes for all inputs

D. Test fails for input 2 only

Solution

1. Step 1: Understand the test logic

   The test asserts num % 2 == 0, meaning num must be even.

2. Step 2: Check each input

   Input 1: 1 % 2 = 1 (fail), Input 2: 2 % 2 = 0 (pass), Input 3: 3 % 2 = 1 (fail).

3. Final Answer:

   Test fails for inputs 1 and 3 -> Option B

4. Quick Check:

   Odd numbers fail assertion [OK]

Hint: Even numbers pass; odd numbers fail [OK]

Common Mistakes:

• Assuming only input 3 fails
• Thinking all inputs pass
• Confusing modulo operation results

4. Identify the error in this data-driven Selenium Python test code snippet:

@pytest.mark.parametrize('username, password', [('user1', 'pass1'), ('user2', 'pass2')])
def test_login(username, password):
    driver.get('http://example.com/login')
    driver.find_element(By.ID, 'username').send_keys(username)
    driver.find_element(By.ID, 'password').send_keys(password)
    driver.find_element(By.ID, 'submit').click()
    assert driver.find_element(By.ID, 'welcome').is_displayed()

medium

A. Missing import for By locator

B. Incorrect parameter names in parametrize decorator

C. Using send_keys on a button element

D. No assertion to check login success

Solution

1. Step 1: Review code for missing imports

   The code uses By.ID but does not show import of By from selenium.webdriver.common.by.

2. Step 2: Check other code parts

   Parameter names match, send_keys used correctly on input fields, assertion checks welcome element display.

3. Final Answer:

   Missing import for By locator -> Option A

4. Quick Check:

   Using By requires importing it [OK]

Hint: Check all used classes are imported [OK]

Common Mistakes:

• Assuming parameter names are wrong
• Thinking send_keys is used on button
• Missing assertion is incorrect here

5. How does using data-driven tests in Selenium Python help maintain and expand test suites efficiently?

hard

A. By allowing reuse of test logic with new data sets without rewriting tests

B. By requiring a new test function for every input variation

C. By limiting tests to only one data set to reduce complexity

D. By removing the need for assertions in tests

Solution

1. Step 1: Understand test maintenance challenges

   Writing separate tests for each input is time-consuming and hard to maintain.

2. Step 2: Explain data-driven test advantage

   Data-driven tests reuse the same test code with different inputs, making it easy to add or change data without rewriting code.

3. Final Answer:

   By allowing reuse of test logic with new data sets without rewriting tests -> Option A

4. Quick Check:

   Reuse test logic + new data = easier maintenance [OK]

Hint: Reuse code, just add data sets [OK]

Common Mistakes:

• Thinking each input needs a new test function
• Believing data-driven tests reduce assertions
• Assuming data-driven tests limit data sets