Temporary directory management in PyTest - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of pytest tmp_path usage

What will be the output of this pytest test function when run?

PyTest

def test_create_file(tmp_path):
    file = tmp_path / "test.txt"
    file.write_text("hello")
    return file.read_text()

A "hello"

B FileNotFoundError

C ""

D AttributeError

💡 Hint

tmp_path is a pathlib.Path object for a temporary directory unique to the test.

The test writes 'hello' to a file in the temporary directory and reads it back, so the output is 'hello'.

❓ assertion

intermediate

Correct assertion for file existence in tmp_path

Which assertion correctly checks that a file named 'data.csv' exists in the pytest tmp_path directory?

A assert tmp_path.exists('data.csv')

B assert tmp_path.has_file('data.csv')

C assert (tmp_path / 'data.csv').exists()

D assert 'data.csv' in tmp_path

💡 Hint

Use pathlib.Path methods to check file existence.

The exists() method on a Path object returns True if the file or directory exists. The other options are invalid methods or syntax.

🔧 Debug

advanced

Identify the error in tmp_path usage

What error will this pytest test raise when executed?

PyTest

def test_write_file(tmp_path):
    file = tmp_path + '/output.txt'
    file.write_text('data')

A TypeError: unsupported operand type(s) for +: 'Path' and 'str'

B FileNotFoundError

C AttributeError: 'str' object has no attribute 'write_text'

D No error, test passes

💡 Hint

Check how to combine pathlib.Path objects with strings.

You cannot use + to join a Path object and a string. Use the / operator instead.

❓ framework

advanced

Behavior of pytest tmp_path fixture scope

Which statement about the pytest tmp_path fixture is true?

A tmp_path is a string path, not a pathlib.Path object

B tmp_path provides a unique temporary directory for each test function invocation

C tmp_path requires manual cleanup of files after each test

D tmp_path creates a single temporary directory shared across all tests in a module

💡 Hint

Consider the isolation pytest provides for tests using tmp_path.

pytest tmp_path fixture creates a new temporary directory for each test function, ensuring isolation and automatic cleanup.

🧠 Conceptual

expert

Why use tmp_path over tempfile.TemporaryDirectory in pytest?

Which is the main advantage of using pytest's tmp_path fixture instead of Python's tempfile.TemporaryDirectory in tests?

A tmp_path only works on Windows systems

B tmp_path creates permanent directories for debugging after tests finish

C tmp_path requires manual cleanup unlike tempfile.TemporaryDirectory

D tmp_path integrates with pytest's test lifecycle and provides pathlib.Path objects for easier file operations

💡 Hint

Think about pytest features and pathlib benefits.

tmp_path is a pytest fixture that automatically manages temporary directories per test and returns pathlib.Path objects, making file handling simpler and integrated with pytest's lifecycle.