Improved coverage

[loiseaujc]

This PR adds the original fftpack testsuite (here) to our set of unit tests. Hopefully, it should cover the last few lines not yet covered by our current suite.

Progress

• dffti, dfftf, dfftb
• dsinti, dsint
• dcosti, dcost
• dcosqi, dcosqf, dcosqb
• dsinqi, dsinqf, dsinqb (functions are not being exported currently)
• dzffti, dzfftf, dzfftb
• zffti, zfftf, zfftb

[codecov]

Codecov Report

❌ Patch coverage is 99.17012% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 81.33%. Comparing base (afcfff6) to head (9343432).
⚠️ Report is 6 commits behind head on main.

Files with missing lines	Patch %	Lines
test/test_fftpack_original.f90	99.17%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #60      +/-   ##
==========================================
- Coverage   82.99%   81.33%   -1.67%     
==========================================
  Files          67       67              
  Lines        2317     2255      -62     
  Branches      182      204      +22     
==========================================
- Hits         1923     1834      -89     
- Misses        394      421      +27     

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[loiseaujc]

I had hoped that including the original fftpack testsuite would cover the lines not already covered but apparently not. At least, it provides unit test for which we know the analytical solution. It is ready for review nonetheless.

Ping: @perazz, @zoziha

[zoziha]

@loiseaujc Thanks for sharing.