add test

Author: ben-schwen

inst/tests/tests.Rraw

@@ -21141,3 +21141,10 @@ dt = data.table(id = 1:25)
 test(2314.1, any(grepl("<int>", tail(capture.output(print(dt, class = TRUE)), 2))), TRUE)
 # Test that class=TRUE with col.names="top" doesn't show classes at bottom
 test(2314.2, !any(grepl("<int>", tail(capture.output(print(dt, class = TRUE, col.names = "top")), 2))), TRUE)
+
+# forderv should not segfault on wide tables due to recursion #4300
+set.seed(1)
+x = matrix(rnorm(1e4), nrow=10)
+idx = sample(10, 20, TRUE)
+DT = as.data.table(x[idx,])
+test(10, length(forderv(DT, by=names(DT), sort=FALSE, retGrp=TRUE)), 20L)