Question
Answer and Explanation
Adding custom data to the pytest JUnit XML output can be achieved through several methods, primarily involving the use of fixtures and hooks provided by pytest. Below is a detailed explanation of the approach and implementation:
1. Understanding the Pytest Hooks:
- Pytest provides hooks which are functions that pytest calls at specific points during test execution. To modify the JUnit XML output, we need to use the pytest_sessionfinish hook which runs after the entire test session.
2. Implementation via pytest_sessionfinish:
- The pytest_sessionfinish hook can access the session's report and allows for direct manipulation of the XML content that is about to be written.
3. Creating a conftest.py file:
- Create a conftest.py file in your test directory, this is where you will implement the custom hook function.
4. Example Code:
# conftest.py
import pytest
from xml.etree import ElementTree as ET
def pytest_sessionfinish(session, exitstatus):
if hasattr(session.config, 'option') and session.config.option.xmlpath:
xml_path = session.config.option.xmlpath
tree = ET.parse(xml_path)
root = tree.getroot()
for testsuite in root.findall('testsuite'):
for testcase in testsuite.findall('testcase'):
testcase.set('custom_data', 'some_value') # Adds or updates attribute to each test case
tree.write(xml_path)
5. Explanation:
- The above code snippet parses the JUnit XML file specified by the --junitxml command-line option.
- It then iterates through each testcase element within the testsuite elements, adding a custom attribute custom_data. You can modify the attribute name and value as needed.
- Finally, it overwrites the original XML file with the modified data. The check if hasattr(session.config, 'option') and session.config.option.xmlpath: verifies if the --junitxml option was even passed to the pytest command line.
6. How to Run:
- To use this, simply run pytest with the --junitxml=output.xml option (or your preferred file path) to produce the XML and have your hook function modify it. For example: pytest --junitxml=test-report.xml
7. Important considerations:
- This approach allows you to add static data to each testcase tag. For data specific to each test case, you'd need to adapt the logic to fetch relevant information from the pytest node object which is available within hooks such as pytest_runtest_makereport or pytest_itemcollected and then cache that information before pytest_sessionfinish.
By implementing these hooks in your conftest.py, you gain significant flexibility in customizing the data included in the JUnit XML output of your Pytest tests.