Merge #1235

1235: Pytest migration r=hgrecco a=hgrecco

- [x] Closes #947  (insert issue number)
- [x] Executed ``pre-commit run --all-files`` with no errors
- [x] The change is fully covered by automated unit tests
- [x] Documented in docs/ as appropriate
- [x] Added an entry to the CHANGES file


Co-authored-by: Hernan <hernan.grecco@gmail.com>
Co-authored-by: Hernan Grecco <hernan.grecco@gmail.com>

.travis.yml

@@ -55,7 +55,7 @@ before_install:
  - export TEST_OPTS="-rfsxEX -s --cov=pint --cov-config=.coveragerc"
 
 install:
- - conda create -n travis $PKGS pytest pytest-cov coveralls
+ - conda create -n travis $PKGS pytest pytest-cov coveralls pytest-subtests
  - source activate travis
  - if [[ $PKGS =~ pandas ]]; then PANDAS=1; else PANDAS=0; fi
  - if [[ $PKGS =~ pre-commit ]]; then LINT=1; else LINT=0; fi

docs/contributing.rst

@@ -3,8 +3,17 @@
 Contributing to Pint
 ====================
 
-You can contribute in different ways:
+Pint uses (and thanks):
+- github_ to host the code
+- travis_ to test all commits and PRs.
+- coveralls_ to monitor coverage test coverage
+- readthedocs_ to host the documentation.
+- `bors-ng`_ as a merge bot and therefore every PR is tested before merging.
+- black_, isort_ and flake8_ as code linters and pre-commit_ to enforce them.
+- pytest_ to write tests
+- sphinx_ to write docs.
 
+You can contribute in different ways:
 
 Report issues
 -------------
@@ -19,18 +28,23 @@ Contribute code
 To contribute fixes, code or documentation to Pint, fork Pint in github_ and submit
 the changes using a pull request against the **master** branch.
 
-- If you are fixing a bug, add a test to test_issues.py, or amend/enrich the general
- test suite to cover the use case.
-- If you are submitting new code, add tests and documentation.
+- If you are submitting new code, add tests (see below) and documentation.
 - Write "Closes #<bug number>" in the PR description or a comment, as described in the
  `github docs`_.
 - Log the change in the CHANGES file.
-- Execute ``black -t py36 . && isort -rc . && flake8`` and resolve any issues.
-
-Pint uses `bors-ng` as a merge bot and therefore every PR is tested before merging.
+- Execute ``pre-commit run --all-files`` and resolve any issues.
 
 In any case, feel free to use the `issue tracker`_ to discuss ideas for new features or improvements.
 
+Notice that we will not merge a PR if tests are failing. In certain cases tests pass in your
+machine but not in travis. There might be multiple reasons for this but these are some of
+the most common
+
+- Your new code does not work for other Python or Numpy versions.
+- The documentation is not being built properly or the examples in the docs are
+ not working.
+- linters are reporting that the code does no adhere to the standards.
+
 
 Setting up your environment
 ---------------------------
@@ -44,6 +58,27 @@ environment on Linux or OSX with the following commands::
  $ source venv/bin/activate
  $ pip install -e .
  $ pip install -r requirements_docs.txt
+ $ pip install pre-commit # This step and the next are optional but recommended.
+ $ pre-commit install
+
+
+Writing tests
+-------------
+
+We use pytest_ for testing. If you contribute code you need to add tests:
+
+- If you are fixing a bug, add a test to `test_issues.py`, or amend/enrich the general
+ test suite to cover the use case.
+- If you are adding a new feature, add a test in the appropiate place. There is usually
+ a `test_X.py` for each `X.py` file. There are some other test files that deal with
+ individual/specific features. If in doubt, ask.
+- Prefer functions to classes.
+- When using classes, derive from `QuantityTestCase`.
+- Use `parametrize` as much as possible.
+- Use `fixtures` (see conftest.py) instead of instantiating the registry yourself.
+- Checkout `helpers.py` for some convenience functions before reinventing the wheel.
+- When your test does not modify the registry, use `sess_registry` fixture.
+
 
 Running tests and building documentation
 ----------------------------------------
@@ -94,3 +129,12 @@ features that work best as an extension pacakage versus direct inclusion in Pint
 .. _`issue tracker`: https://github.com/hgrecco/pint/issues
 .. _`bors-ng`: https://github.com/bors-ng/bors-ng
 .. _`github docs`: https://help.github.com/articles/closing-issues-via-commit-messages/
+.. _travis: https://travis-ci.com/
+.. _coveralls: https://coveralls.io/
+.. _readthedocs: https://readthedocs.org/
+.. _pre-commit: https://pre-commit.com/
+.. _black: https://black.readthedocs.io/en/stable/
+.. _isort: https://pycqa.github.io/isort/
+.. _flake8: https://flake8.pycqa.org/en/latest/
+.. _pytest: https://docs.pytest.org/en/stable/
+.. _sphinx: https://www.sphinx-doc.org/en/master/

pint/testsuite/__init__.py

@@ -1,141 +1,26 @@
 import doctest
-import logging
 import math
 import os
 import unittest
-from contextlib import contextmanager
-from logging.handlers import BufferingHandler
 
-from pint import Quantity, UnitRegistry, logger
-from pint.compat import ndarray, np
+from pint import UnitRegistry
 from pint.testsuite.helpers import PintOutputChecker
 
 
-class TestHandler(BufferingHandler):
- def __init__(self, only_warnings=False):
- # BufferingHandler takes a "capacity" argument
- # so as to know when to flush. As we're overriding
- # shouldFlush anyway, we can set a capacity of zero.
- # You can call flush() manually to clear out the
- # buffer.
- self.only_warnings = only_warnings
- BufferingHandler.__init__(self, 0)
-
- def shouldFlush(self):
- return False
-
- def emit(self, record):
- if self.only_warnings and record.level != logging.WARNING:
- return
- self.buffer.append(record.__dict__)
-
-
-class BaseTestCase(unittest.TestCase):
-
- CHECK_NO_WARNING = True
-
- @contextmanager
- def capture_log(self, level=logging.DEBUG):
- th = TestHandler()
- th.setLevel(level)
- logger.addHandler(th)
- if self._test_handler is not None:
- buflen = len(self._test_handler.buffer)
- yield th.buffer
- if self._test_handler is not None:
- self._test_handler.buffer = self._test_handler.buffer[:buflen]
-
- def setUp(self):
- self._test_handler = None
- if self.CHECK_NO_WARNING:
- self._test_handler = th = TestHandler()
- th.setLevel(logging.WARNING)
- logger.addHandler(th)
-
- def tearDown(self):
- if self._test_handler is not None:
- buf = self._test_handler.buffer
- msg = "\n".join(record.get("msg", str(record)) for record in buf)
- self.assertEqual(len(buf), 0, msg=f"{len(buf)} warnings raised.\n{msg}")
-
-
-class QuantityTestCase(BaseTestCase):
-
- FORCE_NDARRAY = False
+class QuantityTestCase:
+ kwargs = {}
 
  @classmethod
- def setUpClass(cls):
- cls.ureg = UnitRegistry(force_ndarray=cls.FORCE_NDARRAY)
+ def setup_class(cls):
+ cls.ureg = UnitRegistry(**cls.kwargs)
  cls.Q_ = cls.ureg.Quantity
  cls.U_ = cls.ureg.Unit
 
- def _get_comparable_magnitudes(self, first, second, msg):
- if isinstance(first, Quantity) and isinstance(second, Quantity):
- second = second.to(first)
- self.assertEqual(
- first.units, second.units, msg=msg + " Units are not equal."
- )
- m1, m2 = first.magnitude, second.magnitude
- elif isinstance(first, Quantity):
- self.assertTrue(
- first.dimensionless, msg=msg + " The first is not dimensionless."
- )
- first = first.to("")
- m1, m2 = first.magnitude, second
- elif isinstance(second, Quantity):
- self.assertTrue(
- second.dimensionless, msg=msg + " The second is not dimensionless."
- )
- second = second.to("")
- m1, m2 = first, second.magnitude
- else:
- m1, m2 = first, second
-
- return m1, m2
-
- def assertQuantityEqual(self, first, second, msg=None):
- if msg is None:
- msg = "Comparing %r and %r. " % (first, second)
-
- m1, m2 = self._get_comparable_magnitudes(first, second, msg)
-
- if isinstance(m1, ndarray) or isinstance(m2, ndarray):
- np.testing.assert_array_equal(m1, m2, err_msg=msg)
- elif math.isnan(m1):
- self.assertTrue(math.isnan(m2), msg)
- elif math.isnan(m2):
- self.assertTrue(math.isnan(m1), msg)
- else:
- self.assertEqual(m1, m2, msg)
-
- def assertQuantityAlmostEqual(self, first, second, rtol=1e-07, atol=0, msg=None):
- if msg is None:
- try:
- msg = "Comparing %r and %r. " % (first, second)
- except TypeError:
- try:
- msg = "Comparing %s and %s. " % (first, second)
- except Exception:
- msg = "Comparing"
-
- m1, m2 = self._get_comparable_magnitudes(first, second, msg)
-
- if isinstance(m1, ndarray) or isinstance(m2, ndarray):
- np.testing.assert_allclose(m1, m2, rtol=rtol, atol=atol, err_msg=msg)
- elif math.isnan(m1):
- self.assertTrue(math.isnan(m2), msg)
- elif math.isnan(m2):
- self.assertTrue(math.isnan(m1), msg)
- else:
- self.assertLessEqual(abs(m1 - m2), atol + rtol * abs(m2), msg=msg)
-
-
-class CaseInsensitveQuantityTestCase(QuantityTestCase):
  @classmethod
- def setUpClass(cls):
- cls.ureg = UnitRegistry(case_sensitive=False)
- cls.Q_ = cls.ureg.Quantity
- cls.U_ = cls.ureg.Unit
+ def teardown_class(cls):
+ cls.ureg = None
+ cls.Q_ = None
+ cls.U_ = None
 
 
 def testsuite():

pint/testsuite/conftest.py

@@ -0,0 +1,77 @@
+# pytest fixtures
+
+import io
+
+import pytest
+
+import pint
+
+
+@pytest.fixture
+def registry_empty():
+ return pint.UnitRegistry(None)
+
+
+@pytest.fixture
+def registry_tiny():
+ return pint.UnitRegistry(
+ io.StringIO(
+ """
+yocto- = 1e-24 = y-
+zepto- = 1e-21 = z-
+atto- = 1e-18 = a-
+femto- = 1e-15 = f-
+pico- = 1e-12 = p-
+nano- = 1e-9 = n-
+micro- = 1e-6 = µ- = u-
+milli- = 1e-3 = m-
+centi- = 1e-2 = c-
+deci- = 1e-1 = d-
+deca- = 1e+1 = da- = deka-
+hecto- = 1e2 = h-
+kilo- = 1e3 = k-
+mega- = 1e6 = M-
+giga- = 1e9 = G-
+tera- = 1e12 = T-
+peta- = 1e15 = P-
+exa- = 1e18 = E-
+zetta- = 1e21 = Z-
+yotta- = 1e24 = Y-
+
+meter = [length] = m = metre
+second = [time] = s = sec
+
+angstrom = 1e-10 * meter = Å = ångström = Å
+minute = 60 * second = min
+"""
+ )
+ )
+
+
+@pytest.fixture
+def func_registry():
+ return pint.UnitRegistry()
+
+
+@pytest.fixture(scope="class")
+def class_registry():
+ """Only use for those test that do not modify the registry."""
+ return pint.UnitRegistry()
+
+
+@pytest.fixture(scope="session")
+def sess_registry():
+ """Only use for those test that do not modify the registry."""
+ return pint.UnitRegistry()
+
+
+@pytest.fixture(scope="class")
+def class_tiny_app_registry():
+ ureg_bak = pint.get_application_registry()
+ ureg = pint.UnitRegistry(None)
+ ureg.define("foo = []")
+ ureg.define("bar = foo / 2")
+ pint.set_application_registry(ureg)
+ assert pint.get_application_registry() is ureg
+ yield ureg
+ pint.set_application_registry(ureg_bak)