## xy.coords() and xyz.coords() -- gets *classed* warning
tools::assertWarning(xy.coords(-2:10, log = "y"), verbose=TRUE)
op <- options(warn = 2)# ==> warnings are errors
suppressWarnings(xy.coords(-2:10, log = "y"), classes="log_le_0") -> xy
stopifnot(identical(xy$y, c(rep(NA_real_,3), 1:10)))
options(op) # (reverting)
tools::assertWarning(xy.coords(-2:10, log = "y"), verbose=TRUE)

## PDF metadata
oopt <- pdf.options(author = "useR", timestamp = FALSE, producer = FALSE)
pdf(f <- tempfile(), title = "test", compress = FALSE); plot.new(); dev.off()
pdflines <- readLines(f)
stopifnot(c("/Title (test)", "/Author (useR)") %in% pdflines,
          !startsWith(pdflines, "/CreationDate"),
          !startsWith(pdflines, "/ModDate"),
          !startsWith(pdflines, "/Producer"))
pdf.options(reset = TRUE)
stopifnot(identical(oopt, pdf.options()))