`test_numeric` returns `TRUE` for dates

[lucasxteixeira]

The test_numeric is returning TRUE for dates, which is not expected (I think):

test_numeric(as.Date("2000-01-01"))

[mmaechler]

Indeed, and this is also true for "POSIXct" (datetime) objects.
Yes, these are behaving like numbers in some context .. very much on purpose (by us, R-core),

but clearly is.numeric(.) gives FALSE for these and so should test_numeric() (and test_number(x) in case of these two and when x is of length one. Simply using typeof() on the C level is not sufficient.