# AN-2026-0752: Python 3.12 removed the deprecated unittest TestCase aliases (assertEquals, assertRegexpMatches, assertRaisesRegexp, failUnless, assert_ ...): "has no attribute 'assertEquals'"

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- id: AN-2026-0752 (version 1; cite https://breakwire.org/claim/AN-2026-0752/v/1)
- kind: breaking · status: active · review: editor
- source: <https://docs.python.org/3/whatsnew/3.12.html#:~:text=Remove%20many%20long%2Ddeprecated%20unittest%20features>
- more sources: <https://github.com/python/cpython/blob/v3.15.2/Objects/object.c> <https://github.com/python/cpython/blob/v3.15.2/Objects/typeobject.c>
- event date: 2023-10-02
- services: python
- affected: engines.python >=3.12
- severity: medium
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. What's New in Python 3.12 (opened 2026-11-04) lists the removed TestCase method aliases with their replacements: failUnless/assert_ -> assertTrue(), failIf -> assertFalse(), failUnlessEqual/assertEquals -> assertEqual(), failIfEqual/assertNotEquals -> assertNotEqual(), assertAlmostEquals -> assertAlmostEqual(), assertNotAlmostEquals -> assertNotAlmostEqual(), failUnlessRaises -> assertRaises(), assertRegexpMatches -> assertRegex(), assertRaisesRegexp -> assertRaisesRegex(), assertNotRegexpMatche  [✓0 ✗0]
1. Reproduced 2026-11-04 on CPython 3.12.16: unittest.TestCase.assertEquals raises AttributeError: type object 'TestCase' has no attribute 'assertEquals'; called on a test instance the message is '<TestClass>' object has no attribute 'assertEquals'.  [✓0 ✗0]

## Fix
```text
Rename to the modern names (assertEquals -> assertEqual, assertRegexpMatches -> assertRegex, assertRaisesRegexp -> assertRaisesRegex, failUnless/assert_ -> assertTrue, failIf -> assertFalse, ...). The What's New page points to the teyit tool to rewrite test suites automatically. Replace assertDictContainsSubset(sub, d) with assertLessEqual(sub.items(), d.items()) or an explicit dict comparison.
```

## Error signatures
- code: `has no attribute 'assertEquals'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'assertNotEquals'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'assertAlmostEquals'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'assertNotAlmostEquals'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'assertRegexpMatches'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'assertRaisesRegexp'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'assertNotRegexpMatches'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'assertDictContainsSubset'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'failUnlessEqual'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'failIfEqual'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'failUnlessRaises'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))
- code: `has no attribute 'failUnless'` (CPython message, reproduced 2026-11-04 on CPython 3.12.16 (TestCase attribute))

## Outcome reports (0)
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## History
- v1 2026-11-04 by wire-editor: filed from primary source opened 2026-10-28