context("shortest_paths")
test_that("shortest_paths works", {
library(igraph)
edges <- matrix(c("s", "a", 2,
"s", "b", 4,
"a", "t", 4,
"b", "t", 2,
"a", "1", 1,
"a", "2", 1,
"a", "3", 2,
"1", "b", 1,
"2", "b", 2,
"3", "b", 1),
byrow=TRUE, ncol=3,
dimnames=list(NULL, c("from", "to", "weight")))
edges <- as.data.frame(edges)
edges[[3]] <- as.numeric(as.character(edges[[3]]))
g <- graph_from_data_frame(as.data.frame(edges))
all1 <- all_shortest_paths(g, "s", "t", weights=NA)$res
all2 <- all_shortest_paths(g, "s", "t")$res
s1 <- shortest_paths(g, "s", "t", weights=NA)
s2 <- get.shortest.paths(g, "s", "t")
expect_true(s1$vpath %in% all1)
expect_true(s2$vpath %in% all2)
})
test_that("shortest_paths can handle negative weights", {
g <- make_tree(7)
E(g)$weight <- -1
sps <- shortest_paths(g, 2)$vpath
expect_true(length(sps) == 7)
expect_equivalent(as.vector(sps[[1]]), integer(0))
expect_equivalent(as.vector(sps[[2]]), c(2))
expect_equivalent(as.vector(sps[[3]]), integer(0))
expect_equivalent(as.vector(sps[[4]]), c(2, 4))
expect_equivalent(as.vector(sps[[5]]), c(2, 5))
expect_equivalent(as.vector(sps[[6]]), integer(0))
expect_equivalent(as.vector(sps[[7]]), integer(0))
})
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