error when no matching rows

[kieranjmartin]

If we have two data frames which do not match on the keys at all, diffdf errors as in #44 and #77 . See reprex

library(dplyr)
library(tibble)
library(diffdf)

X <- tibble(STUDYID = "B", USUBJID = "B", ASEQ = "B", SUBJID = "B")

Y <- tibble(STUDYID = "A", USUBJID = "A", ASEQ = "A", SUBJID = "A")

diffdf(X, Y, keys = c("STUDYID", "USUBJID", "ASEQ"))

It's clear to me that in this case diffdf should report something useful; as both data sets have contents, but no matches.