[FIX] handle case when dummy_scans is 0

[jdkent]

fixes #437

adds tests to confirm functionality.

[pull-assistant]

Best reviewed: commit by commit

---

Optimal code review plan (1 warning)

handle case when dummy_scans is 0

niworkflows/func/util.py 50% changes removed in Apply suggestions fr...

     Apply suggestions from code review

Powered by Pull Assistant. Last update 84c99d6 ... 748e726. Read the comment docs.

[oesteban]

Sorry, I did not think that zero would be evaluated to False. Just an stylistic nitpick.

[codecov]

Codecov Report

Merging #438 into master will decrease coverage by 5.08%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #438      +/-   ##
==========================================
- Coverage   59.93%   54.84%   -5.09%     
==========================================
  Files          57       42      -15     
  Lines        5443     4801     -642     
  Branches      643      644       +1     
==========================================
- Hits         3262     2633     -629     
+ Misses       2138     2049      -89     
- Partials       43      119      +76

Flag	Coverage Δ
#masks	?
#reportlettests	?
#unittests	?

Impacted Files	Coverage Δ
niworkflows/func/util.py	28% <100%> (-50.09%)	⬇️
niworkflows/interfaces/fixes.py	41.17% <0%> (-45.1%)	⬇️
niworkflows/interfaces/ants.py	57.81% <0%> (-16.15%)	⬇️
niworkflows/engine/workflows.py	26.31% <0%> (-15.79%)	⬇️
niworkflows/interfaces/bids.py	80.15% <0%> (-15.48%)	⬇️
niworkflows/interfaces/utility.py	75.47% <0%> (-13.21%)	⬇️
niworkflows/utils/bids.py	75.94% <0%> (-12.81%)	⬇️
niworkflows/interfaces/itk.py	28.39% <0%> (-10.5%)	⬇️
niworkflows/interfaces/registration.py	51.72% <0%> (-10.35%)	⬇️
... and 23 more

---

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 5e833f9...748e726. Read the comment docs.

[effigies]

LGTM. Obviously correct, so I'm +1 for merging without waiting on tests.