@pytest.mark.skipif with condition - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of test skipped condition

What will be the result of running this pytest test function?

import sys
import pytest

@pytest.mark.skipif(sys.platform == 'win32', reason='Skip on Windows')
def test_example():
    assert True

PyTest

import sys
import pytest

@pytest.mark.skipif(sys.platform == 'win32', reason='Skip on Windows')
def test_example():
    assert True

A Test is skipped only on Windows platform

B Test runs and passes on all platforms

C Test fails on Windows platform

D Test is skipped on all platforms

💡 Hint

Think about what sys.platform returns and how skipif uses it.

The decorator @pytest.mark.skipif skips the test only if the condition is True. Here, the condition is sys.platform == 'win32', so the test is skipped only on Windows.

❓ assertion

intermediate

Assertion outcome with skipif condition

Given this test code, what is the assertion outcome when run on Linux?

import sys
import pytest

@pytest.mark.skipif(sys.platform != 'linux', reason='Only run on Linux')
def test_value():
    assert 2 + 2 == 4

PyTest

import sys
import pytest

@pytest.mark.skipif(sys.platform != 'linux', reason='Only run on Linux')
def test_value():
    assert 2 + 2 == 4

A Test is skipped on Linux

B Test runs and assertion passes on Linux

C Test runs and assertion fails on Linux

D Test is skipped on all platforms

💡 Hint

Check the condition sys.platform != 'linux' and what it means on Linux.

The skipif condition is True if platform is not Linux. On Linux, condition is False, so test runs and assertion passes.

🔧 Debug

advanced

Identify error in skipif usage

What error will this pytest code raise when run?

import pytest

@pytest.mark.skipif('sys.platform == "darwin"', reason='Skip on Mac')
def test_func():
    assert True

PyTest

import pytest

@pytest.mark.skipif('sys.platform == "darwin"', reason='Skip on Mac')
def test_func():
    assert True

A TypeError because condition is a string, not a boolean

B Test is skipped on MacOS

C Test runs and passes on all platforms

D SyntaxError due to wrong quotes

💡 Hint

Check the type of the condition argument in skipif.

The condition argument must be a boolean expression, not a string. Passing a string causes TypeError.

❓ framework

advanced

Using skipif with environment variable

Which option correctly skips a test if the environment variable TEST_ENV is not set to 'prod'?

PyTest

import os
import pytest

@pytest.mark.skipif(____, reason='Skip if not prod environment')
def test_env():
    assert True

A os.getenv('TEST_ENV') == 'prod'

B os.environ['TEST_ENV'] == 'prod'

C os.environ.get('TEST_ENV') == 'prod'

D os.getenv('TEST_ENV') != 'prod'

💡 Hint

Remember skipif skips when condition is True.

We want to skip if TEST_ENV is not 'prod', so condition should be True when env is not 'prod'. Option D correctly expresses that.

🧠 Conceptual

expert

Behavior of skipif with dynamic condition

Consider this test code:

import pytest
import random

@pytest.mark.skipif(random.choice([True, False]), reason='Random skip')
def test_random():
    assert True

What is the expected behavior when running pytest multiple times?

PyTest

import pytest
import random

@pytest.mark.skipif(random.choice([True, False]), reason='Random skip')
def test_random():
    assert True

A Test is randomly skipped or run each pytest run

B Test is always run because skipif ignores dynamic conditions

C Test is always skipped because condition is evaluated once at import

D Test raises an error due to random in skipif

💡 Hint

Think about when skipif condition is evaluated.

skipif condition is evaluated once when tests are collected, not at each test run. So random.choice is called once per pytest session, making skip or run fixed per run.

Practice

1. What is the main purpose of using @pytest.mark.skipif in a test?

easy

A. To skip a test when a specific condition is true

B. To run a test multiple times

C. To mark a test as expected to fail

D. To automatically fix test failures

Solution

1. Step 1: Understand the decorator purpose

   @pytest.mark.skipif is used to skip tests conditionally.

2. Step 2: Identify the correct use case

   It skips tests only if the given condition evaluates to True, preventing unsuitable test runs.

3. Final Answer:

   To skip a test when a specific condition is true -> Option A

4. Quick Check:

   Skip test if condition true [OK]

Hint: Skip tests only when condition is true [OK]

Common Mistakes:

• Confusing skipif with parametrize
• Using skipif without a condition
• Thinking skipif runs tests multiple times

2. Which of the following is the correct syntax to skip a test if Python version is less than 3.8?

easy

A. @pytest.mark.skipif(sys.version_info < (3, 8), reason='Python < 3.8')

B. @pytest.skipif(sys.version_info < (3, 8), reason='Python < 3.8')

C. @pytest.mark.skipif(sys.version < 3.8, reason='Python < 3.8')

D. @pytest.mark.skipif(sys.version_info <= 3.8, reason='Python < 3.8')

Solution

1. Step 1: Check correct decorator usage

   The correct decorator is @pytest.mark.skipif, not @pytest.skipif.

2. Step 2: Verify condition and syntax

   Python version is checked with sys.version_info tuple; comparison uses < (less than) and tuple format (3, 8).

3. Final Answer:

   @pytest.mark.skipif(sys.version_info < (3, 8), reason='Python < 3.8') -> Option A

4. Quick Check:

   Correct decorator and version tuple [OK]

Hint: Use sys.version_info tuple with @pytest.mark.skipif [OK]

Common Mistakes:

• Using @pytest.skipif instead of @pytest.mark.skipif
• Comparing sys.version instead of sys.version_info
• Using <= instead of < for version check

3. Given the code below, what will happen when running the test on a Windows system?

import sys
import pytest

@pytest.mark.skipif(sys.platform != 'win32', reason='Only runs on Windows')
def test_windows_feature():
    assert True

medium

A. The test will raise a syntax error

B. The test will always run regardless of platform

C. The test will fail on Windows systems

D. The test will be skipped on non-Windows systems

Solution

1. Step 1: Analyze the skip condition

   The condition sys.platform != 'win32' means skip if platform is not Windows.

2. Step 2: Determine behavior on Windows

   On Windows, sys.platform == 'win32', so condition is False, test runs. On other OS, condition True, test skipped.

3. Final Answer:

   The test will be skipped on non-Windows systems -> Option D

4. Quick Check:

   Skip if not Windows [OK]

Hint: Condition True means skip; False means run test [OK]

Common Mistakes:

• Thinking test runs only on non-Windows
• Confusing != with == in condition
• Assuming syntax error from decorator

4. Identify the error in the following pytest code snippet:

import pytest

@pytest.mark.skipif(reason='No condition provided')
def test_example():
    assert True

medium

A. Reason argument should be outside skipif

B. Incorrect import statement for pytest

C. Missing condition argument in skipif decorator

D. Missing assert statement in test

Solution

1. Step 1: Check skipif decorator usage

   @pytest.mark.skipif requires a condition argument to decide when to skip.

2. Step 2: Identify missing condition

   Here, only reason is provided, no condition, so syntax is invalid.

3. Final Answer:

   Missing condition argument in skipif decorator -> Option C

4. Quick Check:

   skipif needs condition argument [OK]

Hint: Always provide condition before reason in skipif [OK]

Common Mistakes:

• Omitting the condition argument
• Placing reason before condition
• Confusing skipif with skip

5. You want to skip a test only if the environment variable TEST_ENV is set to production. Which of the following is the correct way to write this using @pytest.mark.skipif?

hard

A. @pytest.mark.skipif(os.environ['TEST_ENV'] == 'production', reason='Skip in production')

B. @pytest.mark.skipif(os.getenv('TEST_ENV') == 'production', reason='Skip in production')

C. @pytest.mark.skipif('TEST_ENV' == 'production', reason='Skip in production')

D. @pytest.mark.skipif(os.getenv('TEST_ENV') != 'production', reason='Skip in production')

Solution

1. Step 1: Understand environment variable access

   Use os.getenv('TEST_ENV') to safely get the variable; it returns None if not set.

2. Step 2: Write correct skip condition

   Skip only if value equals 'production', so condition is os.getenv('TEST_ENV') == 'production'.

3. Step 3: Check other options

   @pytest.mark.skipif('TEST_ENV' == 'production', reason='Skip in production') compares string literals, not env variable. @pytest.mark.skipif(os.environ['TEST_ENV'] == 'production', reason='Skip in production') may raise KeyError if variable missing. @pytest.mark.skipif(os.getenv('TEST_ENV') != 'production', reason='Skip in production') skips when not production, opposite of requirement.

4. Final Answer:

   @pytest.mark.skipif(os.getenv('TEST_ENV') == 'production', reason='Skip in production') -> Option B

5. Quick Check:

   Use os.getenv and == 'production' for skipif [OK]

Hint: Use os.getenv for safe env check in skipif [OK]

Common Mistakes:

• Using os.environ without handling missing keys
• Comparing strings directly instead of env variable
• Reversing the skip condition logic