d <- mtcars[seq(6L), ] names(d) <- paste0("..coord", seq(ncol(d))) m <- cmdscale_ord(dist(d), k = 3L) m <- as_tbl_ord(m) test_that("all available 'StatSpantree' engines work", { n_mst <- (nrow(m) - 1L) * 2L { skip_if_not_installed("mlpack") p <- ggbiplot(m) + stat_spantree(ord_aes(m), engine = "mlpack") expect_equal(nrow(layer_data(p)), n_mst) } { skip_if_not_installed("vegan") p <- ggbiplot(m) + stat_spantree(ord_aes(m), engine = "vegan") expect_equal(nrow(layer_data(p)), n_mst) } { skip_if_not_installed("ade4") p <- ggbiplot(m) + stat_spantree(ord_aes(m), engine = "ade4") expect_equal(nrow(layer_data(p)), n_mst) } })