fix failing tests on Linux

[IndrajeetPatil]

• closes Unit tests fail under Linux #881
• closes Get rid of NOTEs and WARNINGs in R CMD Check #884
• removes the brittle snapshot test; uses it as an example instead

[IndrajeetPatil]

@Yuri05 For 3.6.3, I see:

Error: package or namespace load failed for 'rClr':
 .onLoad failed in loadNamespace() for 'rClr', details:
  call: inDL(x, as.logical(local), as.logical(now), ...)
  error: unable to load shared object 'c:/RLibrary/3.6/rClr/libs/x64/rClrMs.dll':
  LoadLibrary failure:  The specified procedure could not be found.
Error: package 'rClr' could not be loaded
In addition: Warning message:
package 'rClr' was built under R version 4.0.4 
Execution halted

How can we simultaneously test for two different R versions and not run into rClr issues?

[msevestre]

You need to install rclr per matrix and not once. Is it possible? (we have two versions of rclr specifically to support >=4 and <4 of R)

[msevestre]

ALternatively, we do not do this with matrix .
Instead we create a nightly that runs only with the 3.6 version of everything. I think it's probably even better so that the actual ospsuite-r build time does not go through the roof

[IndrajeetPatil]

Instead we create a nightly that runs only with the 3.6 version of everything

I like it!

[IndrajeetPatil]

It's important to test on 4.1.0 now because visual regression tests are running only on R > 4.1.

[IndrajeetPatil]

@msevestre You have the last laugh with snapshot test 😭

I don't see the difference between these.

expected

actual (on AppVeyor)

SVG shows difference here: stroke-linejoin: miter; is present in one, but not the other. No clue why.

  < <line x1='577.99' y1='320.91' x2='690.32' y2='320.91' style='stroke-width: 2.1
  : 3; stroke: #333333; stroke-linecap: butt; stroke-linejoin: miter;' />         
  > <line x1='577.99' y1='320.91' x2='690.32' y2='320.91' style='stroke-width: 2.1
  : 3; stroke: #333333; stroke-linecap: butt;' /> 

[Yuri05]

@IndrajeetPatil @PavelBal @msevestre
Do we want to have tlf and patchwork as mandatory prerequisites (like now) or is it sufficient to have them as optional prereqs?
I would vote for optional, because - except for plots - ospsuite is still fully functional without those packages installed.

[IndrajeetPatil]

Honestly speaking, I think this function (plotGrid()) should live in tlf. It sticks out like a sore thumb in ospsuite at the moment. We can re-export it from ospsuite for convenience, but it doesn't feel like its natural home.

In any case, I can move tlf and patchwork to Suggests.

[IndrajeetPatil]

But I think this should be part of a separate PR. This is not in the scope of the current PR.

[Yuri05]

I think this function should live in tlf.

Which function?

[IndrajeetPatil]

plotGrid()

[IndrajeetPatil]

It's a general plotting function with no ties to DataCombined, and so more appropriate for tlf than ospsuite.

[Yuri05]

ah ok. Yes, I agree. Would expect it in the tlf as well.

[IndrajeetPatil]

Cool, I will create a separate issue to track this, both here and in tlf.