Unit tests for pilot3 adam functions (character formatters and the like used in the R programs)

[robertdevine]

@SHAESEN2, @bms63, @laxamanaj, @kaz462 - Per pilot3utils unit testing, here we'll use testthat( ) also.
This will target the character format functions from earlier in the project that are located in this repo. thx.

[robertdevine]

@laxamanaj, @bms63 - infrastructure in place to start unit tests with pilot3 package including the ADaM character formatters from earlier in the project. We'll put in ~100 unit tests so we have good test coverage here as well. thx.

[bms63]

Hey @robertdevine I'm reluctant to create unit tests for this repo as it isn't really an R package. 100 unit tests is a quite lot of effort and I'm not sure how much value it will add to the project at the end of the day.

The unit tests in the other package was just an "icing on the cake" part due to the re-submission.

@bms63, @laxamanaj - there was a request (above) to add unit test coverage for the character formatters found in the pilot3 package. Unit tests to cover just the character formatters used earlier during pilot3 will limit the effort to a dozen or so additional unit tests and provide the requested value add. Proceed or should I close the Issue?

If proceed, then PR gets pushed this week. thx.

@bms63, @laxamanaj, @SHAESEN2 - upon further research, the pilot3utils package does not specifically call the R/user_utils.R functions - however, the R/user_utils.R functions were used earlier in the pilot3 package with
the ADaM data sets. So a middle course here is to include the unit tests for the R/user_utils.R functions with the
pilot3utils unit tests - that was the original ask of @SHAESEN2. The R/user_utils.R function (character formatters,
etc.) were used earlier in the pilot.

So, in summary, this pilot3 issue gets transferred to Issue #2 in pilot3utils and then closed as complete. thx.