* Put a 'reset' color in front of the highlighting
When doing the highlighting, some lexers will not set the initial color
explicitly, which may lead to the red from the errors being propagated
to the start of the expression
* Add syntactic highlighting to the error explanations
This updates the various error reporting to highlight python code when
displayed, to increase readability and make it easier to understand
Previously the error report would have all sections glued together:
- The assertion representation
- The error explanation
- The full diff
This makes it hard to see at a glance where which one starts and ends.
One of the representation (dataclasses, tuples, attrs) does display a
newlines at the start already.
Let's add a newlines before the error explanation and before the full
diff, so we get an easier to read report.
This has one disadvantage: we get one line less in the least verbose
mode, where the output gets truncated.
When running `tox -e py-lsof` I get a deluge of this warning:
```
src/pytest/.tox/py-lsof-numpy-pexpect/lib/python3.11/site-packages/_pytest/pytester.py:130: EncodingWarning: UTF-8 Mode affects locale.getpreferredencoding(). Consider locale.getencoding() instead.
```
Use `locale.getencoding` instead.
The normal default pretty printer is not great when objects are nested
and it can get hard to read the diff.
Instead, provide a pretty printer that behaves more like when json get
indented, which allows for smaller, more meaningful differences, at
the expense of a slightly longer diff.
This does not touch the other places where the pretty printer is used,
and only updated the full diff one.
We already have the AlwaysDispatchingPrettyPrinter override of the
default pretty printer. In order to make more in depth changes, we
need to copy the upstream version in, as it doesn't lend itself well to
being extended.
This does a verbatime copy, adding provenance information at the top.
The current method as the following problem, described by Sadra
Barikbin:
The tests that request both `pytester` and `monkeypatch` and use
`monkeypatch.chdir` without context, relying on `monkeypatch`'s teardown
to restore cwd. This doesn't work because the following sequence of
actions take place:
- `monkeypatch` is set up.
- `pytester` is set up. It saves the original cwd and changes it to a
new one dedicated to the test function.
- Test function calls `monkeypatch.chdir()` without context.
`monkeypatch` saves cwd, which is not the original one, before
changing it.
- `pytester` is torn down. It restores the cwd to the original one.
- `monkeypatch` is torn down. It restores cwd to what it has saved.
The solution here is to have pytester use `monkeypatch.chdir()` itself,
then everything is handled correctly.
Tests if a captured exception group contains an expected exception.
Will raise `AssertionError` if the wrapped exception is not an exception group.
Supports recursive search into nested exception groups.
