Built-in markers (skip, skipif, xfail) in PyTest - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to skip the test unconditionally.

PyTest

import pytest

@pytest.mark.[1]()
def test_example():
    assert 1 == 1

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

Askip

Bskipif

Cxfail

Dmark

Attempts:

3 left

💡 Hint

Common Mistakes

Using @pytest.mark.skipif without a condition

Using @pytest.mark.xfail which marks expected failure, not skip

The @pytest.mark.skip() marker skips the test unconditionally.

2fill in blank

medium

Complete the code to skip the test only if Python version is less than 3.8.

PyTest

import pytest
import sys

@pytest.mark.[1](sys.version_info < (3, 8))
def test_feature():
    assert True

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

Askipif

Bskip

Cxfail

Dmark

Attempts:

3 left

💡 Hint

Common Mistakes

Using @pytest.mark.skip without condition

Using @pytest.mark.xfail which marks expected failure

The @pytest.mark.skipif(condition) marker skips the test only if the condition is true.

3fill in blank

hard

Fix the error in the code to mark the test as expected to fail.

PyTest

import pytest

@pytest.mark.[1]()
def test_buggy():
    assert 1 == 2

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

Amark

Bskip

Cskipif

Dxfail

Attempts:

3 left

💡 Hint

Common Mistakes

Using @pytest.mark.skip() which skips the test

Using @pytest.mark.skipif(True) which skips unconditionally

The @pytest.mark.xfail() marker marks the test as expected to fail.

4fill in blank

hard

Fill both blanks to skip the test if the platform is Windows and mark it as expected to fail otherwise.

PyTest

import pytest
import sys

@pytest.mark.[1](sys.platform == 'win32')
@pytest.mark.[2](sys.platform != 'win32')
def test_platform():
    assert False

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

Askipif

Bskip

Cxfail

Dmark

Attempts:

3 left

💡 Hint

Common Mistakes

Using unconditional skip which can't be conditional

Mixing skip and skipif incorrectly

Use @pytest.mark.skipif(sys.platform == 'win32') to skip on Windows, and @pytest.mark.xfail(sys.platform != 'win32') to mark expected failure otherwise. The skipif takes precedence if its condition is true.

5fill in blank

hard

Fill the blanks to skip the test if Python version is less than 3.7, xfail if on Linux, and run normally otherwise.

PyTest

import pytest
import sys
import platform

@pytest.mark.[1](sys.version_info < (3, 7))
@pytest.mark.[2](platform.system() == 'Linux')
def test_conditions():
    assert True

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

Askipif

Bskip

Cxfail

Dmark

Attempts:

3 left

💡 Hint

Common Mistakes

Using non-existent marker like xfailif

Using skip instead of skipif for version check

Use @pytest.mark.skipif(sys.version_info < (3, 7)) to skip if Python < 3.7, and @pytest.mark.xfail(platform.system() == 'Linux') to xfail on Linux. Runs normally if Python ≥ 3.7 and not Linux.

Practice

1. What does the @pytest.mark.skip marker do in a test?

easy

A. It retries the test multiple times before failing.

B. It runs the test only if a condition is true.

C. It marks the test as expected to fail but still runs it.

D. It always skips the test, so it does not run.

Solution

1. Step 1: Understand the purpose of @pytest.mark.skip

   This marker tells pytest to skip the test unconditionally, so the test is not executed at all.

2. Step 2: Compare with other markers

   skipif skips conditionally, and xfail marks expected failures but runs the test. So only skip always skips.

3. Final Answer:

   It always skips the test, so it does not run. -> Option D

4. Quick Check:

   @pytest.mark.skip always skips = D [OK]

Hint: Skip always means test won't run at all [OK]

Common Mistakes:

• Confusing skip with skipif (conditional skip)
• Thinking xfail skips the test
• Assuming skip reruns the test

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

easy

A. @pytest.mark.skipif(sys.version_info < (3, 8)\ndef test_func(): pass

B. @pytest.mark.skipif(sys.version_info < (3, 8), reason='Python < 3.8')\ndef test_func(): pass

C. @pytest.mark.skipif(sys.version_info < 3.8)\ndef test_func(): pass

D. @pytest.mark.skipif(sys.version_info < '3.8')\ndef test_func(): pass

Solution

1. Step 1: Check correct version tuple comparison syntax

   Python version info is a tuple like (3, 7, 5). So comparisons must use tuples, e.g., (3, 8).

2. Step 2: Verify correct use of skipif with reason

   @pytest.mark.skipif(sys.version_info < (3, 8), reason='Python < 3.8')\ndef test_func(): pass uses tuple comparison and includes a reason string, which is best practice for clarity.

3. Final Answer:

   @pytest.mark.skipif(sys.version_info < (3, 8), reason='Python < 3.8')\ndef test_func(): pass -> Option B

4. Quick Check:

   Use tuple and reason in skipif = C [OK]

Hint: Use tuple for version and add reason in skipif [OK]

Common Mistakes:

• Using float instead of tuple for version
• Omitting reason argument
• Comparing version to string

3. What will be the test result when running this code?

import pytest

@pytest.mark.xfail
def test_example():
    assert 1 == 2

medium

A. Test is marked as expected failure but does not fail the suite.

B. Test fails and is reported as failed.

C. Test passes because xfail ignores failures.

D. Test is skipped and not run.

Solution

1. Step 1: Understand @pytest.mark.xfail behavior

   This marker means the test is expected to fail. If it fails, pytest reports it as an expected failure, not a hard failure.

2. Step 2: Analyze the assertion

   The assertion 1 == 2 is false, so the test fails. Because of xfail, this failure is expected and reported accordingly.

3. Final Answer:

   Test is marked as expected failure but does not fail the suite. -> Option A

4. Quick Check:

   xfail means expected failure = A [OK]

Hint: xfail means failure is expected, not a hard fail [OK]

Common Mistakes:

• Thinking xfail skips the test
• Assuming test passes despite assertion
• Confusing xfail with skipif

4. Identify the error in this pytest code snippet:

import pytest

@pytest.mark.skipif(sys.platform == 'win32')
def test_func():
    assert True

medium

A. Missing import of sys module causes NameError.

B. skipif should be skip to always skip the test.

C. The condition syntax is incorrect; should use double equals.

D. The test function must return a value.

Solution

1. Step 1: Check imports used in condition

   The condition uses sys.platform, but sys is not imported, causing a NameError at runtime.

2. Step 2: Verify other parts

   The condition syntax is correct with ==, skipif is valid, and test functions do not need to return values.

3. Final Answer:

   Missing import of sys module causes NameError. -> Option A

4. Quick Check:

   Missing import sys = A [OK]

Hint: Always import modules used in skipif conditions [OK]

Common Mistakes:

• Forgetting to import sys
• Confusing skipif with skip
• Expecting test functions to return values

5. You want to mark a test that should be skipped on Windows and expected to fail on Python versions below 3.7. Which is the correct way to combine skipif and xfail markers?

hard

A. @pytest.mark.xfail(sys.version_info < (3,7, reason='Expected fail on old Python')\[e-mail](sys.platform == 'win32', reason='Skip on Windows')\ndef test_func(): pass

B. @pytest.mark.skipif(sys.platform == 'win32' and sys.version_info < (3,7))\ndef test_func(): pass

C. @pytest.mark.skipif(sys.platform == 'win32', reason='Skip on Windows')\[e-mail](sys.version_info < (3,7), reason='Expected fail on old Python')\ndef test_func(): pass

D. @pytest.mark.skipif(sys.platform == 'win32')\[e-mail](sys.version_info < (3,7))\ndef test_func(): pass

Solution

1. Step 1: Understand marker order and logic

   Tests should be skipped on Windows unconditionally, so skipif for Windows must be applied first.

2. Step 2: Apply xfail conditionally for Python versions below 3.7

   The xfail marker is applied second to mark expected failures on old Python versions.

3. Step 3: Verify option correctness

   @pytest.mark.skipif(sys.platform == 'win32', reason='Skip on Windows')\[e-mail](sys.version_info < (3,7), reason='Expected fail on old Python')\ndef test_func(): pass applies skipif first, then xfail, both with reasons. This is the correct and clear approach.

4. Final Answer:

   Use skipif for Windows, then xfail for Python version condition with reasons. -> Option C

5. Quick Check:

   Skip first, then xfail with reasons = B [OK]

Hint: Apply skipif first, then xfail with clear reasons [OK]

Common Mistakes:

• Reversing marker order causing unexpected runs
• Combining conditions incorrectly in one skipif
• Omitting reason strings for markers