Single parameter in PyTest - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of pytest single parameter test

What is the output of this pytest test when run?

PyTest

import pytest

@pytest.mark.parametrize('num', [1, 2, 3])
def test_is_positive(num):
    assert num > 0

if __name__ == '__main__':
    pytest.main(['-v'])

A SyntaxError during test collection

B 1 test passed, 2 failed

C 3 tests passed

D All tests skipped

💡 Hint

Each parameter value runs the test once.

The test runs three times with num=1, 2, and 3. All are positive, so all pass.

❓ assertion

intermediate

Assertion failure with single parameter

Given this test, which input causes the assertion to fail?

PyTest

import pytest

@pytest.mark.parametrize('value', [1, 2, -1])
def test_positive(value):
    assert value > 0

A value = 1

B value = -1

C value = 0

D All values pass

💡 Hint

Check which values are not greater than zero.

Only -1 is less than or equal to zero, so the assertion fails for value = -1.

❓ locator

advanced

Best locator for pytest parameter name

Which locator correctly identifies the parameter name in this pytest decorator?

PyTest

@pytest.mark.parametrize('input_value', [10, 20])
def test_func(input_value):
    assert input_value > 0

A JSON path for parameter list

B XPath locating function name 'test_func'

C CSS selector for function body

D Regex matching 'parametrize\('([^']+)'

💡 Hint

The parameter name is inside the string in parametrize decorator.

The parameter name is the string inside the parametrize decorator. Regex can extract it reliably.

🔧 Debug

advanced

Debugging failing pytest parameter test

Why does this pytest test fail?

PyTest

import pytest

@pytest.mark.parametrize('x', [1, 2, 3])
def test_double(x):
    assert x * 2 == '2', 'Expected double to be string "2"'

A Comparing int to str causes assertion failure

B SyntaxError in parametrize decorator

C TypeError because x is not iterable

D Test passes without error

💡 Hint

Check the types compared in the assertion.

The test compares an integer (x*2) to a string '2', causing assertion failure but no TypeError.

❓ framework

expert

Effect of single parameter on test count in pytest

If a pytest test uses @pytest.mark.parametrize with a single parameter having 4 values, how many test cases are executed?

PyTest

import pytest

@pytest.mark.parametrize('val', [10, 20, 30, 40])
def test_val(val):
    assert val > 0

A 4 test cases executed

B 1 test case executed

C 16 test cases executed

D 0 test cases executed

💡 Hint

Each parameter value runs the test once.

Each value in the parameter list runs the test once, so 4 values mean 4 test cases.