PHPUnit test classes with camel case or underscore

class String
  def underscore
    self.gsub(/::/, '/').
    gsub(/([A-Z]+)([A-Z][a-z])/,'\1_\2').
    gsub(/([a-z\d])([A-Z])/,'\1_\2').
    tr("-", "_").
    downcase
  end
end

"CamelCase".underscore
=> "camel_case"

// This must be undescored due to naming constrictions
setContentView(R.layout.my_long_layout_name);

// Now this looks a little out of place
findViewById(R.id.myLongSpecificId);

toUnderscore <- function(x) {
  x2 <- gsub("([A-Za-z])([A-Z])([a-z])", "\\1_\\2\\3", x)
  x3 <- gsub(".", "_", x2, fixed = TRUE)
  x4 <- gsub("([a-z])([A-Z])", "\\1_\\2", x3)
  x5 <- tolower(x4)
  x5
}

underscore2camel <- function(x) {
  gsub("_(.)", "\\U\\1", x, perl = TRUE)
}

#######################################################
# test
#######################################################

u <- toUnderscore(as.Given)
u
## [1] "icu_days"   "sex_code"   "max_of_mld" "age_group" 

underscore2camel(u)
## [1] "icuDays"  "sexCode"  "maxOfMld" "ageGroup"

public class WPPostResponse {
    @JsonAlias("featured_media")
    Long featuredMedia;

    public Long getFeaturedMedia() {
        return featuredMedia;
    }

    public void setFeaturedMedia(Long featuredMedia) {
        this.featuredMedia = featuredMedia;
    }
}