Return the design table associated with the test set from an object.
Examples
ds <- gen_sample_dataset(D = c(4, 4, 4), nobs = 10, external_test = TRUE)
#> external test
test_design(ds$design)
#> # A tibble: 10 × 2
#> Ytest .rownum
#> <fct> <int>
#> 1 b 1
#> 2 a 2
#> 3 e 3
#> 4 c 4
#> 5 a 5
#> 6 e 6
#> 7 b 7
#> 8 c 8
#> 9 d 9
#> 10 d 10