pytest-ast-back-to-python
A plugin for pytest devs to view how assertion rewriting recodes the AST
Features
Pytest rewrites the AST (abstract syntax tree) of your tests, for the purpose of displaying the subexpressions involved in your assert statements. This plugin converts that rewritten AST back to Python source, and displays it.
Installation
You can install "pytest-ast-back-to-python" via pip from PyPI:
$ pip install pytest-ast-back-to-python
Usage
py.test --show-ast-as-pythonExample
Take a trivial test like:
def test_simple():
a = 1
b = 2
assert a + b == 3View the rewritten AST as Python like this:
$ py.test --show-ast-as-python test_simple.py
======================================== test session starts ========================================
plugins: ast-back-to-python-0.1.0, cov-2.2.1
collected 1 items
test_simple.py .
======================================== Rewritten AST as Python ========================================
import builtins as @py_builtins
import _pytest.assertion.rewrite as @pytest_ar
def test_simple():
a = 1
b = 2
@py_assert2 = a + b
@py_assert4 = 3
@py_assert3 = @py_assert2 == @py_assert4
if @py_assert3 is None:
from _pytest.warning_types import PytestAssertRewriteWarning
from warnings import warn_explicit
warn_explicit(PytestAssertRewriteWarning('asserting the value None, please use "assert is None"'), category=None, filename='/home/tom/.virtualenvs/tmp-483cf04ecc31dda8/test_thing.py', lineno=4)
if not @py_assert3:
@py_format6 = @pytest_ar._call_reprcompare(('==',), (@py_assert3,), ('(%(py0)s + %(py1)s) == %(py5)s',), (@py_assert2, @py_assert4)) % {'py0': @pytest_ar._saferepr(a) if 'a' in @py_builtins.locals() or @pytest_ar._should_repr_global_name(a) else 'a', 'py1': @pytest_ar._saferepr(b) if 'b' in @py_builtins.locals() or @pytest_ar._should_repr_global_name(b) else 'b', 'py5': @pytest_ar._saferepr(@py_assert4)}
@py_format8 = ('' + 'assert %(py7)s') % {'py7': @py_format6}
raise AssertionError(@pytest_ar._format_explanation(@py_format8))
@py_assert2 = @py_assert3 = @py_assert4 = NoneContributing
Contributions are very welcome. Tests can be run with tox, please ensure the coverage at least stays the same before you submit a pull request.
License
Distributed under the terms of the BSD-3 license, "pytest-ast-back-to-python" is free and open source software
This Pytest plugin was generated with Cookiecutter along with @hackebrot's Cookiecutter-pytest-plugin template.
Issues
If you encounter any problems, please file an issue along with a detailed description.
