custom data.frame classes redirected to as.data.frame before as.data.table

[jangorecki]

closes #5699

[MichaelChirico]

Hi @jangorecki would you mind summarizing what needs to be done to get this ready for review? That way someone else could have a go at sewing it up if you don't get to it first. Thanks!

[jangorecki]

Examine why test fails, if still fails.

[MichaelChirico]

I am OK to merge with Jan's ack (and a NEWS entry).

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.62%. Comparing base (d263924) to head (ae8c6ff).
Report is 1 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5700   +/-   ##
=======================================
  Coverage   98.62%   98.62%           
=======================================
  Files          79       79           
  Lines       14630    14631    +1     
=======================================
+ Hits        14429    14430    +1     
  Misses        201      201           

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[github-actions]

Generated via commit 9633663

Download link for the artifact containing the test results: ↓ atime-results.zip

Task	Duration
R setup and installing dependencies	4 minutes and 39 seconds
Installing different package versions	7 minutes and 51 seconds
Running and plotting the test cases	2 minutes and 20 seconds