There are state transitions start/done/suspend/resume and two additional
operations snap/writeorg.
Previously it was not well defined in what order they can be called, and
which operations are idempotent.
Formalize this and enforce using assert checks with informative error
messages if they fail (rather than random AttributeErrors).
`TerminalWriter`, imported recently from `py`, contains its own
incomplete wcwidth (`char_with`/`get_line_width`) implementation. The
`TerminalReporter` also needs this, but uses the external `wcwidth`
package.
This commit brings the `TerminalWriter` implementation up-to-par with
`wcwidth`, moves to implementation to a new file `_pytest._io.wcwidth`
which is used everywhere, and removes the dependency.
The differences compared to the `wcwidth` package are:
- Normalizes the string before counting.
- Uses Python's `unicodedata` instead of vendored Unicode tables. This
means the data corresponds to the Python's version Unicode version
instead of the `wcwidth`'s package version.
- Apply some optimizations.
_pytest.timing is an indirection to 'time' functions, which pytest production
code should use instead of 'time' directly.
'mock_timing' is a new fixture which then mocks those functions, allowing us
to write time-reliable tests which run instantly and are not flaky.
This was triggered by recent flaky junitxml tests on Windows related to timing
issues.
The `FDCapture`/`FDCaptureBinary` classes, used by `capfd`/`capfdbinary`
fixtures and the `--capture=fd` option (set by default), redirect FDs
1/2 (stdout/stderr) to a temporary file. To do this, they need to save
the old file by duplicating the FD before redirecting it, to be restored
once finished.
Previously, if this duplicating (`os.dup()`) failed, most likely due to
that FD being invalid, the FD redirection would silently not be done. The
FD capturing also performs python-level redirection (monkeypatching
`sys.stdout`/`sys.stderr`) which would still be done, but direct writes
to the FDs would fail.
This is not great. If pytest is run with `--capture=fd`, or a test is
using `capfd`, it expects writes to the FD to work and be captured,
regardless of external circumstances.
So, instead of disabling FD capturing, keep the redirection to a
temporary file, just don't restore it after closing, because there is
nothing to restore to.
Currently, a bad logging call, e.g.
logger.info('oops', 'first', 2)
triggers the default logging handling, which is printing an error to
stderr but otherwise continuing.
For regular programs this behavior makes sense, a bad log message
shouldn't take down the program. But during tests, it is better not to
skip over such mistakes, but propagate them to the user.
