tests: expand are_adjacent() tests

Author: szhorvat

tests/testthat/test-are.connected.R tests/testthat/test-are_adjacent.Rtests/testthat/test-are.connected.R renamed to tests/testthat/test-are_adjacent.R

@@ -4,10 +4,13 @@ test_that("are_adjacent works", {
   expect_true(are_adjacent(g, "B", "A"))
   expect_false(are_adjacent(g, "A", "D"))
 
-  g2 <- make_graph(c(1, 2, 2, 3, 3, 4), dir = FALSE)
+  g2 <- make_graph(c(1,2, 2,3, 3,4, 1,1, 3,4), directed = FALSE)
   expect_true(are_adjacent(g2, 1, 2))
   expect_true(are_adjacent(g2, 3, 2))
+  expect_true(are_adjacent(g2, 3, 4))
+  expect_true(are_adjacent(g2, 1, 1))
   expect_false(are_adjacent(g2, 4, 1))
+  expect_false(are_adjacent(g2, 3, 3))
 
   g3 <- graph_from_literal(A -+ B -+ C, B -+ D)
   expect_false(are_adjacent(g3, "A", "C"))