round to specific intervals

Dear R users/helpers,

I am wondering is there an existing function in which you can round
numbers to a set of values. I know you can use 5 * round(x/5) for
rounding to the nearest 5 or so, but what if the interval size is not
constant.

For example:
## Not run
test<- rnorm(100)
round(test, c(1, 5, 10, 20, 50))

so that the test is rounded to the closest value in the vector.