Addopts for default options in PyTest - Test Execution Trace

Test Overview

This test verifies that pytest runs with default options specified in the pytest.ini file using the addopts setting. It checks that verbose output is enabled by default due to -v from addopts.

Test Code - PyTest

PyTest

import subprocess

def test_pytest_addopts_default():
    # Run pytest with no extra options, relying on addopts in pytest.ini
    result = subprocess.run(['pytest', 'test_sample.py'], capture_output=True, text=True)
    # Check that verbose output is present due to -v from addopts
    assert "::" in result.stdout
    assert result.returncode == 0

Execution Trace - 3 Steps

Step	Action	System State	Assertion	Result
1	Test runner starts subprocess to run 'pytest test_sample.py' without extra options	Command line runs pytest with default options from pytest.ini addopts	—	PASS
2	Pytest loads configuration and applies addopts '-v' for verbose output	Pytest runs tests with verbose output enabled	—	PASS
3	Test subprocess completes and returns output	Captured stdout includes verbose test names and statuses	Check that '::' is in stdout (verbose indicator) and return code is 0	PASS

Failure Scenario

Failing Condition: The addopts setting in pytest.ini is missing or incorrect, so verbose output is not enabled by default

Execution Trace Quiz - 3 Questions

What does the addopts setting in pytest.ini do in this test?

A It adds default command-line options like '-v' when pytest runs

B It disables all command-line options

C It changes the test file name

D It skips tests automatically

Key Result

Using addopts in pytest.ini helps set default command-line options so tests run consistently without needing to specify options every time.

Practice

1. What is the main purpose of the addopts setting in a pytest.ini file?

easy

A. To set default command-line options for pytest runs

B. To define test case names automatically

C. To specify the Python version for pytest

D. To list all test files explicitly

Solution

1. Step 1: Understand addopts role in pytest.ini

   addopts is used to provide default command-line options so you don't have to type them every time.

2. Step 2: Compare other options

   Other options like naming tests or Python version are not controlled by addopts.

3. Final Answer:

   To set default command-line options for pytest runs -> Option A

4. Quick Check:

   Default pytest options = addopts [OK]

Hint: Remember: addopts sets default pytest command options [OK]

Common Mistakes:

• Thinking addopts defines test names
• Confusing addopts with Python version settings
• Assuming addopts lists test files

2. Which of the following is the correct way to add default options in pytest.ini using addopts?

easy

A. [pytest]
addopts = maxfail=3 verbose

B. [pytest]
addopts: --maxfail=3 --verbose

C. [pytest]
addopts = --maxfail=3 --verbose

D. [pytest]
addopts --maxfail=3 --verbose

Solution

1. Step 1: Check correct syntax for ini files

   In pytest.ini, options are set as key = value pairs under [pytest] section.

2. Step 2: Validate option format

   Options must be space-separated strings with dashes, e.g., --maxfail=3 --verbose.

3. Final Answer:

   [pytest]\naddopts = --maxfail=3 --verbose -> Option C

4. Quick Check:

   Ini syntax uses = and spaces for addopts [OK]

Hint: Use '=' after addopts and space-separated options [OK]

Common Mistakes:

• Using ':' instead of '='
• Omitting dashes before options
• Not placing options under [pytest] section

3. Given this pytest.ini content:

[pytest]
addopts = --maxfail=2 --tb=short

What will happen when you run pytest tests/ without extra options?

medium

A. Pytest runs all tests and shows full tracebacks

B. Pytest stops after 2 failures and shows short tracebacks

C. Pytest ignores addopts and runs normally

D. Pytest throws a syntax error due to addopts

Solution

1. Step 1: Understand addopts effect on pytest run

   The options --maxfail=2 and --tb=short set limits on failures and traceback style by default.

2. Step 2: Predict behavior without extra command-line options

   Since addopts sets defaults, pytest will stop after 2 failures and show short tracebacks automatically.

3. Final Answer:

   Pytest stops after 2 failures and shows short tracebacks -> Option B

4. Quick Check:

   addopts options apply by default [OK]

Hint: Default options run automatically without typing them [OK]

Common Mistakes:

• Assuming addopts is ignored
• Thinking full tracebacks show by default
• Expecting all tests to run despite maxfail

4. You added addopts = --maxfail=1 --verbose to pytest.ini but pytest still runs all tests without stopping early. What is the likely cause?

medium

A. The pytest.ini file is not in the current directory or pytest root

B. The --maxfail option does not work with addopts

C. You must run pytest with --use-addopts flag

D. Verbose mode disables maxfail stopping

Solution

1. Step 1: Check pytest.ini location

   Pytest only reads pytest.ini if it is in the current directory or a parent directory of the test run.

2. Step 2: Understand addopts behavior

   If pytest.ini is misplaced, addopts settings are ignored and default pytest behavior occurs.

3. Final Answer:

   The pytest.ini file is not in the current directory or pytest root -> Option A

4. Quick Check:

   pytest.ini location affects addopts usage [OK]

Hint: Ensure pytest.ini is in the test root folder [OK]

Common Mistakes:

• Believing maxfail needs special flags
• Thinking verbose disables maxfail
• Ignoring pytest.ini file location

5. You want pytest to always run tests with coverage report and stop after 5 failures by default. Which addopts line in pytest.ini achieves this correctly?

hard

A. [pytest]
addopts: --cov src --maxfail=5

B. [pytest]
addopts = maxfail=5 --cov src

C. [pytest]
addopts = --maxfail=5 --cov=src --stop

D. [pytest]
addopts = --cov=src --maxfail=5

Solution

1. Step 1: Understand correct option syntax

   Coverage option requires --cov=src with equals sign; maxfail uses --maxfail=5.

2. Step 2: Check for invalid or missing syntax

   Options without '=' or extra unknown flags like --stop are incorrect.

3. Final Answer:

   [pytest]\naddopts = --cov=src --maxfail=5 -> Option D

4. Quick Check:

   Use '=' for options with values in addopts [OK]

Hint: Use '=' for options with values like --cov=src [OK]

Common Mistakes:

• Omitting '=' in options with values
• Adding unsupported flags like --stop
• Switching order without '=' causing errors