increase unit testing robustness

[andersone1]

@barrettk @seth127

Kyle,

The updates you did for the unit tests for mrgda (specifically around svn manipulation) to make them more robust and also to work with renv was extremely helpful. If / when you have time, the review package could benefit from those same enhancements (review also has a lot of tests based on svn).

[barrettk]

@andersone1

FYI the package seemed to work immediately after using renv:

`devtools::test()`

```r > renv::init(bare=T) Restarting R session... Restarting R session... * Project '/data/Projects/package_dev/review' loaded. [renv 0.14.0] > devtools::test() ℹ Testing review ✔ | F W S OK | Context ✔ | 3 | diffFiles ✔ | 8 | diffPreviousRevisions [1.7s] ✔ | 2 | diffQC ✔ | 12 | dirPending [1.5s] ✔ | 2 | getQcedRevision ✔ | 2 | logAccept ✔ | 1 | logAssign ✔ | 1 | logCreate ✔ | 3 | logPending ✔ | 2 | logSummary ✔ | 6 | relpath [2.6s] ══ Results ═══════════════════════════════════════════════════════════════════════════════════════════════════════════════════════ Duration: 9.9 s [ FAIL 0 | WARN 0 | SKIP 0 | PASS 42 ] ```

I opened a new branch to update the pkgr file though