Switch MET's R-based differencing logic over to using the Python-based METplus implementation

[JohnHalleyGotway]

Describe the Enhancement

The existing testing infrastructure for MET uses Perl to run the unit tests defined in each XML file. #2717 switches the Perl control logic over to Python. This task is to reimplement the R-based differencing logic in MET to using Python-based implementation in METplus.

The comp_*.sh scripts in the bin directory are just wrappers to the R functions defined in the R_test directory.

This line of test_regression.sh calls comp_dir.sh to compare the output generated by 2 different runs of the unit tests. That script should be updated to run the Python-based METplus differencing logic instead. The current METplus differencing logic can be found in diff_util.py.

Note that additional work may be required to enhance the METplus differencing logic. For example, if the unit tests are enhanced in #2717 to store runtime and resource (i.e. memory) consumption information, the differencing logic should be enhanced to compare those outputs between 2 runs.

Time Estimate

2 weeks? But please update as needed.

Sub-Issues

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None needed at this time.

Relevant Deadlines

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Funding Source

@natalieb-noaa is funded through the DTC to work on METplus tasks.

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Define Related Issue(s)

Consider the impact to the other METplus components.

• METplus, MET, METdataio, METviewer, METexpress, METcalcpy, METplotpy
• May need a new METplus issue to enhance its differencing logic as needed are identified.

Enhancement Checklist

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