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Use a simple +- ASCII string in the string representation of pytest.approx In Python 2
Fix #2111
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Lines changed: 49 additions & 23 deletions

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‎CHANGELOG.rst‎

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@@ -15,6 +15,11 @@
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* Provide ``:ref:`` targets for ``recwarn.rst`` so we can use intersphinx referencing.
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Thanks to `@dupuy`_ for the report and `@lwm`_ for the PR.
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* In Python 2, use a simple ``+-`` ASCII string in the string representation of ``pytest.approx`` (for example ``"4 +- 4.0e-06"``)
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because it is brittle to handle that in different contexts and representations internally in pytest
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which can result in bugs such as `#2111`_. In Python 3, the representation still uses ``±`` (for example ``4 ± 4.0e-06``).
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Thanks `@kerrick-lyft`_ for the report and `@nicoddemus`_ for the PR.
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* Using ``item.Function``, ``item.Module``, etc., is now issuing deprecation warnings, prefer
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``pytest.Function``, ``pytest.Module``, etc., instead (`#2034`_).
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Thanks `@nmundar`_ for the PR.
@@ -42,25 +47,27 @@
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*
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.. _@mbukatov: https://github.com/mbukatov
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.. _@dupuy: https://bitbucket.org/dupuy/
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.. _@d-b-w: https://bitbucket.org/d-b-w/
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.. _@lwm: https://github.com/lwm
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.. _@adler-j: https://github.com/adler-j
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.. _@d-b-w: https://bitbucket.org/d-b-w/
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.. _@DuncanBetts: https://github.com/DuncanBetts
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.. _@dupuy: https://bitbucket.org/dupuy/
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.. _@kerrick-lyft: https://github.com/kerrick-lyft
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.. _@lwm: https://github.com/lwm
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.. _@mbukatov: https://github.com/mbukatov
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.. _@nedbat: https://github.com/nedbat
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.. _@nmundar: https://github.com/nmundar
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.. _#2089: https://github.com/pytest-dev/pytest/issues/2089
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.. _#478: https://github.com/pytest-dev/pytest/issues/478
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.. _#687: https://github.com/pytest-dev/pytest/issues/687
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.. _#2016: https://github.com/pytest-dev/pytest/issues/2016
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.. _#2034: https://github.com/pytest-dev/pytest/issues/2034
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.. _#2038: https://github.com/pytest-dev/pytest/issues/2038
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.. _#2078: https://github.com/pytest-dev/pytest/issues/2078
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.. _#2082: https://github.com/pytest-dev/pytest/issues/2082
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.. _#2089: https://github.com/pytest-dev/pytest/issues/2089
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.. _#2103: https://github.com/pytest-dev/pytest/issues/2103
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.. _#2105: https://github.com/pytest-dev/pytest/issues/2105
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.. _#2111: https://github.com/pytest-dev/pytest/issues/2111
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.. _#478: https://github.com/pytest-dev/pytest/issues/478
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.. _#687: https://github.com/pytest-dev/pytest/issues/687
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3.0.4

‎_pytest/python.py‎

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@@ -1434,16 +1434,10 @@ def __repr__(self):
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except ValueError:
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vetted_tolerance = '???'
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plus_minus = u'{0} \u00b1 {1}'.format(self.expected, vetted_tolerance)
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# In python2, __repr__() must return a string (i.e. not a unicode
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# object). In python3, __repr__() must return a unicode object
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# (although now strings are unicode objects and bytes are what
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# strings were).
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if sys.version_info[0] == 2:
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return plus_minus.encode('utf-8')
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return '{0} +- {1}'.format(self.expected, vetted_tolerance)
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else:
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return plus_minus
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return u'{0} \u00b1 {1}'.format(self.expected, vetted_tolerance)
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def __eq__(self, actual):
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# Short-circuit exact equality.

‎testing/python/approx.py‎

Lines changed: 33 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
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# encoding: utf-8
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import sys
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import pytest
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import doctest
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@@ -9,6 +9,7 @@
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from fractions import Fraction
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inf, nan = float('inf'), float('nan')
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class MyDocTestRunner(doctest.DocTestRunner):
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def __init__(self):
@@ -22,13 +23,17 @@ def report_failure(self, out, test, example, got):
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class TestApprox:
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def test_repr_string(self):
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# Just make sure the Unicode handling doesn't raise any exceptions.
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print(approx(1.0))
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print(approx([1.0, 2.0, 3.0]))
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print(approx(inf))
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print(approx(1.0, rel=nan))
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print(approx(1.0, rel=inf))
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print(approx(1.0j, rel=inf))
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# for some reason in Python 2.6 it is not displaying the tolerance representation correctly
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plus_minus = u'\u00b1' if sys.version_info[0] > 2 else u'+-'
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tol1, tol2, infr = '1.0e-06', '2.0e-06', 'inf'
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if sys.version_info[:2] == (2, 6):
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tol1, tol2, infr = '???', '???', '???'
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assert repr(approx(1.0)) == '1.0 {pm} {tol1}'.format(pm=plus_minus, tol1=tol1)
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assert repr(approx([1.0, 2.0])) == '1.0 {pm} {tol1}, 2.0 {pm} {tol2}'.format(pm=plus_minus, tol1=tol1, tol2=tol2)
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assert repr(approx(inf)) == 'inf'
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assert repr(approx(1.0, rel=nan)) == '1.0 {pm} ???'.format(pm=plus_minus)
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assert repr(approx(1.0, rel=inf)) == '1.0 {pm} {infr}'.format(pm=plus_minus, infr=infr)
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assert repr(approx(1.0j, rel=inf)) == '1j'
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def test_operator_overloading(self):
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assert 1 == approx(1, rel=1e-6, abs=1e-12)
@@ -285,3 +290,23 @@ def test_doctests(self):
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runner = MyDocTestRunner()
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runner.run(test)
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def test_unicode_plus_minus(self, testdir):
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"""
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Comparing approx instances inside lists should not produce an error in the detailed diff.
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Integration test for issue #2111.
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"""
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testdir.makepyfile("""
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import pytest
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def test_foo():
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assert [3] == [pytest.approx(4)]
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""")
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expected = '4.0e-06'
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# for some reason in Python 2.6 it is not displaying the tolerance representation correctly
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if sys.version_info[:2] == (2, 6):
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expected = '???'
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result = testdir.runpytest()
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result.stdout.fnmatch_lines([
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'*At index 0 diff: 3 != 4 * {0}'.format(expected),
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'=* 1 failed in *=',
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])
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