Subprocess testing in PyTest - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to run a subprocess command that lists files.

PyTest

import subprocess

def test_list_files():
    result = subprocess.run(['ls', '[1]'], capture_output=True, text=True)
    assert result.returncode == 0

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

A-z

B-a

C-x

D-l

Attempts:

3 left

💡 Hint

Common Mistakes

Using an invalid option that causes the subprocess to fail.

Forgetting to capture output which is needed for assertions.

The -a option lists all files including hidden ones. It is a common flag for ls.

2fill in blank

medium

Complete the code to check that the subprocess output contains the word 'test'.

PyTest

import subprocess

def test_output_contains_test():
    result = subprocess.run(['echo', 'this is a test'], capture_output=True, text=True)
    assert [1] in result.stdout

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

A'test'

B'Test'

C'TEST'

D'testing'

Attempts:

3 left

💡 Hint

Common Mistakes

Using a different case which causes the assertion to fail.

Checking for a substring not present in the output.

The output contains the exact word 'test' in lowercase, so the assertion checks for 'test'.

3fill in blank

hard

Fix the error in the subprocess call to correctly capture output as text.

PyTest

import subprocess

def test_capture_text():
    result = subprocess.run(['echo', 'hello'], [1]=True, capture_output=True)
    assert result.stdout.strip() == 'hello'

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

Atext

Bencoding

Cshell

Duniversal_newlines

Attempts:

3 left

💡 Hint

Common Mistakes

Using text=True in older Python versions where it is unsupported.

Not setting any argument, causing output to be bytes.

The universal_newlines=True argument makes stdout a string instead of bytes in Python 3.7+. Alternatively, text=True can be used in newer versions.

4fill in blank

hard

Fill both blanks to run a subprocess that checks Python version and asserts success.

PyTest

import subprocess

def test_python_version():
    result = subprocess.run(['[1]', '[2]'], capture_output=True, text=True)
    assert result.returncode == 0

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

Apython3

Bpython

C--version

D-V

Attempts:

3 left

💡 Hint

Common Mistakes

Using python3 when only python is available.

Using an invalid flag that causes the command to fail.

The command python -V prints the Python version and returns 0 on success.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension filtering files ending with '.py'.

PyTest

import subprocess

def test_list_python_files():
    result = subprocess.run(['ls'], capture_output=True, text=True)
    files = { [1]: True for [2] in result.stdout.splitlines() if [3].endswith('.py') }
    assert 'test_script.py' in files

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

Afile

Bf

Cfilename

Attempts:

3 left

💡 Hint

Common Mistakes

Using different variable names inconsistently causing NameError.

Not filtering files ending with '.py' correctly.

Using the same variable f for key, loop variable, and condition is correct and consistent.