Adds python interface to MaterialType and Material.

[LolaSegura]

🎉 New feature

Related to #101 #210

Summary

Adds Python interface for three math classes: MaterialType, Material. For each Material a python test has been created.

Related issues and notes

MaterialType

This file contains an enum class declaration. Swig supports strongly typed enumerations, so binding this wasn't a problem. But the result was a series of variables contained in the module ignition.math defined as MaterialType_MATERIAL. A work around is needed to be implemented in order to follow the pep-8 naming convention.

Material

The test is not passing.

• This class contains a method Predefined() that returns a reference to an std::map<MaterialType, Material>. In SignalStatsa map was used as well, so a similar approach was taken for this case. There are two main differences in both of this classes:

  • In SignalStats the map is returned as a copy and
  • the types of the map are std::string and double.

• In the case of Material the method is not being wrapped correctly. Instead of being part of the Material class, is defined outside of it, and when it is used in the test as follow:

  mats = ignition.math.Material.predefined() 
  

  it arises an error:

  swig/python detected a memory leak of type 'unknown', no destructor found.
     TypeError: unhashable type: 'SwigPyObject'
     The above exception was the direct cause of the following exception:
  
      Traceback (most recent call last):
       File "/ws/src/ign-math/src/python/Material_TEST.py", line 22, in test_init
          mats = ignition.math.Material.predefined()
      SystemError: <built-in function Material_predefined> returned a result with an error set 
  
  
  

Checklist

• Signed all commits for DCO
• Added tests
• Added example and/or tutorial
• Updated documentation (as needed)
• Updated migration guide (as needed)
• codecheck passed (See contributing)
• All tests passed (See test coverage)
• While waiting for a review on your PR, please help review another open pull request to support the maintainers

Note to maintainers: Remember to use Squash-Merge

[codecov]

Codecov Report

Merging #234 (0e5fb4a) into ign-math6 (23a24d7) will not change coverage.
The diff coverage is n/a.

❗ Current head 0e5fb4a differs from pull request most recent head e69094b. Consider uploading reports for the commit e69094b to get more accurate results

@@            Coverage Diff             @@
##           ign-math6     #234   +/-   ##
==========================================
  Coverage      99.41%   99.41%           
==========================================
  Files             67       67           
  Lines           6347     6347           
==========================================
  Hits            6310     6310           
  Misses            37       37           

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[ahcorde]

friendly ping @scpeters

[francocipollone]

Thanks @ahcorde for taking over the PR and completing it! 🚀