context("layout_with_sugiyama")

test_that("layout_with_sugiyama does not demote matrices to vectors in res$layout.dummy", {
    ex <- graph.formula( A -+ B:C, B -+ C:D)
    layex <- layout.sugiyama(ex, layers=NULL)
    expect_that(nrow(layex$layout.dummy), equals(1))
})

