Do not consider incompetent jobs to be killed

[blueyed]

Fixes #336.

[codecov-io]

Codecov Report

Merging #337 into master will decrease coverage by 0.11%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master     #337      +/-   ##
==========================================
- Coverage   83.33%   83.21%   -0.12%     
==========================================
  Files          46       46              
  Lines        1416     1418       +2     
  Branches      138      138              
==========================================
  Hits         1180     1180              
- Misses        216      218       +2     
  Partials       20       20

Flag	Coverage Δ
#py34	83.07% <0%> (-0.12%)	⬇️
#py35	82.93% <0%> (-0.12%)	⬇️
#py36	82.93% <0%> (-0.12%)	⬇️
#pynightly	82.93% <0%> (-0.12%)	⬇️

Impacted Files	Coverage Δ
cosmic_ray/reporting.py	39.06% <0%> (-1.27%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 48e55c4...34ee4bf. Read the comment docs.

[blueyed]

Is this code really not covered?
Or is it not picked up by pytest-cov correctly?
Experimenting in #338, #339 and #340.

[abingham]

It may not be covered. It's definitely stuff I haven't spent a lot of testing time on.

[abingham]

One problem with this change is that the survival_rate() method needs to be updated. It needs to consider "incompetent" mutants as killed, or at least as "not survivors". I guess this points to the need for a test that generates an incompetent mutants as well (which should just be another issue).