> ## Documentation Index
> Fetch the complete documentation index at: https://docs.virtualityhub.com/llms.txt
> Use this file to discover all available pages before exploring further.
# Testing
> Write and run pytest tests against your V-Run Python workflows in the same cloud sandbox as production — so every commit ships verified code.
V-Run has built-in testing so you can verify your workflow logic before you commit.
## Writing tests
Switch to the **Test** tab in the editor and write standard pytest tests against your main code.
```python theme={null}
from main import parse_articles
def test_parse_articles_returns_list():
html = "Article 1
Article 2
"
result = parse_articles(html)
assert isinstance(result, list)
assert len(result) == 2
def test_parse_articles_empty_page():
html = ""
result = parse_articles(html)
assert result == []
```
Your test code can import functions from `main` (your main code file) directly.
## Running tests
Click **Run Tests** in the editor toolbar. Tests execute in the same cloud sandbox as production runs, so the environment is identical.
Results display in the bottom panel with:
* **Pass/fail status** for each test
* **stdout and stderr** output
* **Execution time**
Run tests frequently during development. They execute in seconds and catch issues before they reach production.
## Test requirements
If your tests need additional packages (e.g. `pytest-mock`, `responses`), add them to the test requirements file. These are installed alongside your main requirements during test execution.
## Best practices
* **Test each function independently.** Import individual functions from your main code rather than running the whole workflow.
* **Cover edge cases.** Test empty inputs, malformed data, and error conditions.
* **Keep tests fast.** Mock external APIs and databases when testing locally to keep the feedback loop tight.
* **Test before committing.** Make it a habit to run the full test suite before you commit a new version.