Handle tests with NIST data as integration tests

[YeungOnion]

Unsure how best to handle these tests, but I think separating them is a good start to not have the data in the repo per #195.

Test suite will rely on environment variable, "STATRS_NIST_DATA_DIR" set as const NIST_DATA_DIR_ENV, to specify path where the files, some listed below, are located.

• lew.txt
• mavro.txt
• numacc1.txt
• ...

Note: I am not married to the usage of an environment variable or its name.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.10%. Comparing base (49a5209) to head (9d88e8a).
Report is 203 commits behind head on master.

❗ Current head 9d88e8a differs from pull request most recent head 494779f

Please upload reports for the commit 494779f to get more accurate results.

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #230      +/-   ##
==========================================
- Coverage   91.76%   90.10%   -1.66%     
==========================================
  Files          44       49       +5     
  Lines        7360    10230    +2870     
==========================================
+ Hits         6754     9218    +2464     
- Misses        606     1012     +406     

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[FreezyLemon]

I like the approach. Maybe add a helper script (bash?) to download the NIST files? Downloading the files manually could be a bit tedious.

[YeungOnion]

We didn't distribute the integration tests with the last release, but if we did, would we want to share the script along with these tests?

[FreezyLemon]

I would logically see the script as a part of that test suite, so yeah.

[YeungOnion]

Will add to CI in another PR, any feedback on this one?

[FreezyLemon]

I tried it on my machine and the script looks good. I think the environment variable works well, no reason to overthink this for a test IMO.

Few ideas to make the experience a bit smoother:

• Add tests/*.dat to the .gitignore so the downloaded files don't show up in git
• Add a bit of output to the script (e.g. Downloading <file>..., Processing <file>...) so we know what's going on. This gets more important when .gitignore includes the data files
• Short comment (top of the nist_tests.rs) that explains how you're intended to actually run the tests would be nice. cargo test -- --include-ignored nist is not obvious IMHO
• Use the current working dir when STATRS_NIST_DATA_DIR is unset. That'd make it easier to cd tests; ./gather_nist_data.sh; cargo test without requiring the env variable

[YeungOnion]

Thanks for the feedback, think it will be clearer and nicer. Opted for default target directory to be tests since manifest and ignore target it and set some sense of working directory.