tomevault-io Sybil Documentation Testing
Sybil validates code examples embedded in documentation and docstrings by parsing and executing them as part of normal test runs.
Official Documentation: https://sybil.readthedocs.io/en/latest/
Installation
pip install sybil[pytest]
Pytest Integration
Configure in conftest.py. See pytest integration docs.
from sybil import Sybil
from sybil.parsers.markdown.codeblock import PythonCodeBlockParser
from sybil.parsers.markdown.skip import SkipParser
pytest_collect_file = Sybil(
parsers=[
SkipParser(),
PythonCodeBlockParser(),
],
patterns=["*.md", "**/*.py"],
).pytest()
Sybil Parameters
See API reference.
| Parameter | Description |
|---|---|
parsers |
Sequence of parser callables |
patterns |
File glob patterns to include (e.g., ["*.md", "src/**/*.py"]) |
excludes |
File glob patterns to exclude |
setup |
Callable receiving namespace dict, called before each document |
teardown |
Callable receiving namespace dict, called after each document |
fixtures |
List of pytest fixture names to inject into namespace |
document_types |
Map file extensions to Document classes |
Document Types
See API reference.
- Default: Parse entire file
PythonDocument: Import.pyfile as module, names available in namespacePythonDocStringDocument: Parse only docstrings from.pyfiles
from sybil.document import PythonDocStringDocument
pytest_collect_file = Sybil(
parsers=[...],
patterns=["src/**/*.py"],
document_types={".py": PythonDocStringDocument},
).pytest()
Fixtures
import pytest
from sybil import Sybil
@pytest.fixture
def my_fixture():
return {"key": "value"}
pytest_collect_file = Sybil(
parsers=[...],
patterns=["*.md"],
fixtures=["my_fixture"], # Available in document namespace
).pytest()
Setup/Teardown
def sybil_setup(namespace):
namespace["helper"] = lambda x: x * 2
def sybil_teardown(namespace):
pass # Cleanup if needed
pytest_collect_file = Sybil(
parsers=[...],
setup=sybil_setup,
teardown=sybil_teardown,
).pytest()
Disable pytest's Built-in Doctest
Add to pyproject.toml to prevent conflicts:
[tool.pytest.ini_options]
addopts = "-p no:doctest"
Markdown Parsers
from sybil.parsers.markdown.codeblock import PythonCodeBlockParser, CodeBlockParser
from sybil.parsers.markdown.skip import SkipParser
from sybil.parsers.markdown.clear import ClearNamespaceParser
Skip Directives
See skip directive docs.
SkipParser must come before other parsers to handle skip directives.
<!-- skip: next -->
```python
# This example is skipped
```
# Skipped and reported as skipped test with reason
# Multiple examples
# All skipped
# Conditionally skipped based on namespace variable
## Invisible Code Blocks
Setup code that doesn't render in documentation. See [invisible code blocks docs](https://sybil.readthedocs.io/en/latest/markdown.html#invisible-code-blocks).
```markdown
<!-- invisible-code-block: python
setup_var = "hidden setup"
-->
Clear Namespace
Reset the document namespace for isolation. See clear namespace docs.
<!-- clear-namespace -->
Custom Evaluators
See evaluators API.
from sybil.parsers.markdown.codeblock import CodeBlockParser
from sybil.evaluators.python import PythonEvaluator
# Custom evaluator with future imports
evaluator = PythonEvaluator(future_imports=["annotations"])
parser = CodeBlockParser(language="python", evaluator=evaluator)
Running Sybil Tests
Sybil tests are collected like regular pytest tests. To run only Sybil tests:
# Run tests from specific directory containing documented code
pytest src/mypackage/ -v
# Exclude regular tests, only run documentation examples
pytest docs/ -v
To exclude Sybil tests from regular test runs, use pytest's --ignore flag or configure addopts in pyproject.toml.
Example: Complete conftest.py
"""Sybil configuration for docstring testing."""
from sybil import Sybil
from sybil.document import PythonDocStringDocument
from sybil.evaluators.python import PythonEvaluator
from sybil.parsers.markdown.codeblock import CodeBlockParser
from sybil.parsers.markdown.skip import SkipParser
import mypackage
def sybil_setup(namespace):
"""Pre-populate namespace for all examples."""
namespace["pkg"] = mypackage
def sybil_teardown(namespace):
"""Cleanup after document."""
pass
pytest_collect_file = Sybil(
parsers=[
SkipParser(),
CodeBlockParser(language="python", evaluator=PythonEvaluator()),
CodeBlockParser(language="py", evaluator=PythonEvaluator()),
],
patterns=["src/mypackage/**/*.py"],
document_types={".py": PythonDocStringDocument},
setup=sybil_setup,
teardown=sybil_teardown,
excludes=[
"**/tests/**",
"**/_internal/**",
],
).pytest()
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