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test_that("has_eulerian_path works", {
g <- graph_from_literal(A - B - C - D - A)
expect_true(has_eulerian_path(g))
g <- graph_from_literal(A - B - C - D - E - A - F - D - B - F - E, simplify = FALSE)
expect_true(has_eulerian_path(g))
g <- graph_from_literal(A - B - C - D - A - D - C, B - D, simplify = FALSE)
expect_false(has_eulerian_path(g))
g <- make_empty_graph(10)
expect_true(has_eulerian_path(g))
})
test_that("eulerian_path works", {
g <- graph_from_literal(A - B - C - D - A)
path <- eulerian_path(g)
path$epath <- as.vector(path$epath)
path$vpath <- as.vector(path$vpath)
expect_equal(path$epath, as.vector(E(g, path = c(1:4, 1))))
expect_equal(path$vpath, c(1:4, 1))
g <- make_empty_graph(10)
path <- eulerian_path(g)
path$epath <- as.vector(path$epath)
path$vpath <- as.vector(path$vpath)
expect_equal(path$epath, numeric(0))
expect_equal(path$vpath, numeric(0))
g <- graph_from_literal(A - B - C - D - E - A - F - D - B - F - E, simplify = FALSE)
path <- eulerian_path(g)
path$epath <- as.vector(path$epath)
path$vpath <- as.vector(path$vpath)
expect_equal(
path$epath,
as.vector(E(g, path = c(1, 2, 3, 4, 2, 6, 1, 5, 4, 6, 5)))
)
expect_equal(path$vpath, c(1, 2, 3, 4, 2, 6, 1, 5, 4, 6, 5))
g <- graph_from_literal(A - B - C - D - A - D - C, B - D, simplify = FALSE)
expect_error(eulerian_path(g), "The graph does not have an Eulerian path")
})
test_that("has_eulerian_cycle works", {
g <- graph_from_literal(A - B - C - D - A)
expect_true(has_eulerian_cycle(g))
g <- graph_from_literal(A - B - C - D - E - A - F - D - B - F - E, simplify = FALSE)
expect_false(has_eulerian_cycle(g))
g <- graph_from_literal(A - B - C - D - A - D - C, B - D, simplify = FALSE)
expect_false(has_eulerian_cycle(g))
g <- make_empty_graph(10)
expect_true(has_eulerian_cycle(g))
})
test_that("eulerian_cycle works", {
g <- graph_from_literal(A - B - C - D - A)
cycle <- eulerian_cycle(g)
cycle$epath <- as.vector(cycle$epath)
cycle$vpath <- as.vector(cycle$vpath)
expect_equal(cycle$epath, as.vector(E(g, path = c(1:4, 1))))
expect_equal(cycle$vpath, c(1:4, 1))
g <- make_empty_graph(10)
cycle <- eulerian_cycle(g)
cycle$epath <- as.vector(cycle$epath)
cycle$vpath <- as.vector(cycle$vpath)
expect_equal(cycle$epath, numeric(0))
expect_equal(cycle$vpath, numeric(0))
g <- graph_from_literal(A - B - C - D - E - A - F - D - B - F - E, simplify = FALSE)
expect_error(eulerian_cycle(g), "The graph does not have an Eulerian cycle")
g <- graph_from_literal(A - B - C - D - A - D - C, B - D, simplify = FALSE)
expect_error(eulerian_cycle(g), "The graph does not have an Eulerian cycle")
})
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