added '-s' option in example command

[bhargavthriler]

Description
The pytest -s option is required to read from stdin.

Checklist

• PR has been tested

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 45.1%. Comparing base (cf3b5ab) to head (55cc233).
��️ Report is 3 commits behind head on master.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@          Coverage Diff           @@
##           master    #447   +/-   ##
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  Coverage    45.1%   45.1%           
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  Files         172     172           
  Lines       13617   13617           
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  Hits         6143    6143           
  Misses       7474    7474           

Flag	Coverage Δ
3.10	45.1% <ø> (ø)
3.11	45.1% <ø> (ø)
3.12	45.1% <ø> (ø)
3.13	45.0% <ø> (ø)
3.14	45.0% <ø> (ø)
3.9	45.1% <ø> (ø)

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[jluebbe]

As the transitions are executed under with capsys.disabled():, the -s switch should not be needed. Is that broken for you?

[Emantor]

Yes, see #443

[jluebbe]

@Emantor, according to https://docs.pytest.org/en/latest/capture.html#accessing-captured-output-from-a-test-function, it should be possible to disable capturing with capsys.disabled(). If that's broken, we should fix it upstream instead of using -s as a workaround.

[Emantor]

pytest-dev/pytest#2189 seems to indicate that we are not alone. Only stdout is not captured, stdin looks to be captured even with capsys.disabled(). I'll look into pytest and determine whether this can be fixed there or we need to have a workaround within labgrid.

[jluebbe]

The capsys docs now refer explicitly to stdout/stderr, so we need to document using -s in the example and with ManualPowerDriver under pytest.