Fix/improve handling of chdir with no-args and testpaths

[blueyed]

Fixes #4332.

[blueyed]

As per https://github.com/pytest-dev/pytest/pull/4317/files#r231699560 there could also be a warning, but that would add an extra os.getcwd() (not too bad though), but I am not really sure how helpful this would be after all.

[codecov]

Codecov Report

Merging #4336 into features will decrease coverage by 0.19%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           features    #4336     +/-   ##
===========================================
- Coverage     95.84%   95.64%   -0.2%     
===========================================
  Files           111      111             
  Lines         24893    24900      +7     
  Branches       2431     2428      -3     
===========================================
- Hits          23858    23816     -42     
- Misses          737      781     +44     
- Partials        298      303      +5

Flag	Coverage Δ
#docs	28.9% <0%> (-0.04%)	⬇️
#doctesting	28.9% <0%> (-0.04%)	⬇️
#linting	28.9% <0%> (-0.04%)	⬇️
#linux	95.43% <100%> (-0.2%)	⬇️
#nobyte	?
#numpy	41.66% <20%> (-51.36%)	⬇️
#pexpect	41.66% <20%> (-0.03%)	⬇️
#py27	93.8% <100%> (-0.22%)	⬇️
#py34	92.15% <100%> (ø)	⬆️
#py35	92.16% <100%> (ø)	⬆️
#py36	93.71% <100%> (-0.2%)	⬇️
#py37	92.21% <100%> (ø)	⬆️
#trial	41.66% <20%> (-51.36%)	⬇️
#windows	93.25% <100%> (-0.72%)	⬇️
#xdist	?

Impacted Files	Coverage Δ
src/_pytest/config/__init__.py	94.66% <100%> (-0.34%)	⬇️
testing/test_collection.py	99.78% <100%> (ø)	⬆️
src/_pytest/reports.py	86.9% <0%> (-10.72%)	⬇️
testing/test_terminal.py	97.46% <0%> (-2.54%)	⬇️
testing/test_junitxml.py	96.15% <0%> (-1.75%)	⬇️
src/_pytest/terminal.py	91.49% <0%> (-1.54%)	⬇️
testing/test_parseopt.py	93.87% <0%> (-0.82%)	⬇️
testing/deprecated_test.py	99.26% <0%> (-0.74%)	⬇️
testing/acceptance_test.py	97.84% <0%> (-0.44%)	⬇️
... and 8 more

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[RonnyPfannschmidt]

you can use self.invocation_dir.join(x, abs=True) and i believe the cast to str is not needed

[blueyed]

The cast to string was needed for xdist.

[RonnyPfannschmidt]

good point, then it is definitively needed for the line below where it sets args = [self.invocation_dir]

[nicoddemus]

👍