set.seed(1)
DF <- data.frame("X" = rnorm(100))
# generate the dummy vector `dummy` using `ifelse()`
# append `dummy` to `DF`
dummy <- ifelse(DF$X > 0, 1, 0)
DF$dummy <- dummy
test_object("dummy")
test_function("ifelse")
test_object("DF")