Align Expected and Actual titles in assert_has_calls/assert_called_with for greater readability

[morisja]

Feature or enhancement

Proposal:

The current output for assert_called_with and assert_has_calls has different spacing making visual identification of simple issues challenging.

Example:

  File "/usr/lib/python3.10/unittest/mock.py", line 929, in assert_called_with
    raise AssertionError(_error_message()) from cause
AssertionError: expected call not found.
Expected: mock('foo', 'bar')
Actual: mock('foo', 'foo')     <-- moving this two chars to the right would be easier to see foo != bar

  File "/usr/lib/python3.10/unittest/mock.py", line 966, in assert_has_calls
    raise AssertionError(
AssertionError: Calls not found.
Expected: [call('foo', 'bar')]
Actual: [call('foo', 'foo')]   <-- moving this two chars to the right would be easier to see foo != bar

I propose whitespace is added preceding Actual: to align as follows:

  File "/usr/lib/python3.10/unittest/mock.py", line 929, in assert_called_with
    raise AssertionError(_error_message()) from cause
AssertionError: expected call not found.
Expected: mock('foo', 'bar')
  Actual: mock('foo', 'foo')

  File "/usr/lib/python3.10/unittest/mock.py", line 966, in assert_has_calls
    raise AssertionError(
AssertionError: Calls not found.
Expected: [call('foo', 'bar')]
  Actual: [call('foo', 'foo')]

I chose preceding to minimize any potential parsing (e.g Actual : would make two fields if split by whitespace)

Has this already been discussed elsewhere?

This is a minor feature, which does not need previous discussion elsewhere

Links to previous discussion of this feature:

I found similar, but not exact discussion here
#79681

Linked PRs

• gh-111019: Align expected and actual titles in test output #111020
• [3.12] gh-111019: Align expected and actual titles in test output (GH-111020) #111024
• [3.11] gh-111019: Align expected and actual titles in test output (GH-111020) #111025

[terryjreedy]

An alternative would have been to click 'Expected' to 'Actual', but verb-adjective is a bit jarring. Indent is fine and alignment will help.