diff env/lib/python3.9/site-packages/networkx/algorithms/tests/test_euler.py @ 0:4f3585e2f14b draft default tip

"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/env/lib/python3.9/site-packages/networkx/algorithms/tests/test_euler.py	Mon Mar 22 18:12:50 2021 +0000
@@ -0,0 +1,191 @@
+import collections
+
+import pytest
+
+import networkx as nx
+
+
+class TestIsEulerian:
+    def test_is_eulerian(self):
+        assert nx.is_eulerian(nx.complete_graph(5))
+        assert nx.is_eulerian(nx.complete_graph(7))
+        assert nx.is_eulerian(nx.hypercube_graph(4))
+        assert nx.is_eulerian(nx.hypercube_graph(6))
+
+        assert not nx.is_eulerian(nx.complete_graph(4))
+        assert not nx.is_eulerian(nx.complete_graph(6))
+        assert not nx.is_eulerian(nx.hypercube_graph(3))
+        assert not nx.is_eulerian(nx.hypercube_graph(5))
+
+        assert not nx.is_eulerian(nx.petersen_graph())
+        assert not nx.is_eulerian(nx.path_graph(4))
+
+    def test_is_eulerian2(self):
+        # not connected
+        G = nx.Graph()
+        G.add_nodes_from([1, 2, 3])
+        assert not nx.is_eulerian(G)
+        # not strongly connected
+        G = nx.DiGraph()
+        G.add_nodes_from([1, 2, 3])
+        assert not nx.is_eulerian(G)
+        G = nx.MultiDiGraph()
+        G.add_edge(1, 2)
+        G.add_edge(2, 3)
+        G.add_edge(2, 3)
+        G.add_edge(3, 1)
+        assert not nx.is_eulerian(G)
+
+
+class TestEulerianCircuit:
+    def test_eulerian_circuit_cycle(self):
+        G = nx.cycle_graph(4)
+
+        edges = list(nx.eulerian_circuit(G, source=0))
+        nodes = [u for u, v in edges]
+        assert nodes == [0, 3, 2, 1]
+        assert edges == [(0, 3), (3, 2), (2, 1), (1, 0)]
+
+        edges = list(nx.eulerian_circuit(G, source=1))
+        nodes = [u for u, v in edges]
+        assert nodes == [1, 2, 3, 0]
+        assert edges == [(1, 2), (2, 3), (3, 0), (0, 1)]
+
+        G = nx.complete_graph(3)
+
+        edges = list(nx.eulerian_circuit(G, source=0))
+        nodes = [u for u, v in edges]
+        assert nodes == [0, 2, 1]
+        assert edges == [(0, 2), (2, 1), (1, 0)]
+
+        edges = list(nx.eulerian_circuit(G, source=1))
+        nodes = [u for u, v in edges]
+        assert nodes == [1, 2, 0]
+        assert edges == [(1, 2), (2, 0), (0, 1)]
+
+    def test_eulerian_circuit_digraph(self):
+        G = nx.DiGraph()
+        nx.add_cycle(G, [0, 1, 2, 3])
+
+        edges = list(nx.eulerian_circuit(G, source=0))
+        nodes = [u for u, v in edges]
+        assert nodes == [0, 1, 2, 3]
+        assert edges == [(0, 1), (1, 2), (2, 3), (3, 0)]
+
+        edges = list(nx.eulerian_circuit(G, source=1))
+        nodes = [u for u, v in edges]
+        assert nodes == [1, 2, 3, 0]
+        assert edges == [(1, 2), (2, 3), (3, 0), (0, 1)]
+
+    def test_multigraph(self):
+        G = nx.MultiGraph()
+        nx.add_cycle(G, [0, 1, 2, 3])
+        G.add_edge(1, 2)
+        G.add_edge(1, 2)
+        edges = list(nx.eulerian_circuit(G, source=0))
+        nodes = [u for u, v in edges]
+        assert nodes == [0, 3, 2, 1, 2, 1]
+        assert edges == [(0, 3), (3, 2), (2, 1), (1, 2), (2, 1), (1, 0)]
+
+    def test_multigraph_with_keys(self):
+        G = nx.MultiGraph()
+        nx.add_cycle(G, [0, 1, 2, 3])
+        G.add_edge(1, 2)
+        G.add_edge(1, 2)
+        edges = list(nx.eulerian_circuit(G, source=0, keys=True))
+        nodes = [u for u, v, k in edges]
+        assert nodes == [0, 3, 2, 1, 2, 1]
+        assert edges[:2] == [(0, 3, 0), (3, 2, 0)]
+        assert collections.Counter(edges[2:5]) == collections.Counter(
+            [(2, 1, 0), (1, 2, 1), (2, 1, 2)]
+        )
+        assert edges[5:] == [(1, 0, 0)]
+
+    def test_not_eulerian(self):
+        with pytest.raises(nx.NetworkXError):
+            f = list(nx.eulerian_circuit(nx.complete_graph(4)))
+
+
+class TestIsSemiEulerian:
+    def test_is_semieulerian(self):
+        # Test graphs with Eulerian paths but no cycles return True.
+        assert nx.is_semieulerian(nx.path_graph(4))
+        G = nx.path_graph(6, create_using=nx.DiGraph)
+        assert nx.is_semieulerian(G)
+
+        # Test graphs with Eulerian cycles return False.
+        assert not nx.is_semieulerian(nx.complete_graph(5))
+        assert not nx.is_semieulerian(nx.complete_graph(7))
+        assert not nx.is_semieulerian(nx.hypercube_graph(4))
+        assert not nx.is_semieulerian(nx.hypercube_graph(6))
+
+
+class TestHasEulerianPath:
+    def test_has_eulerian_path_cyclic(self):
+        # Test graphs with Eulerian cycles return True.
+        assert nx.has_eulerian_path(nx.complete_graph(5))
+        assert nx.has_eulerian_path(nx.complete_graph(7))
+        assert nx.has_eulerian_path(nx.hypercube_graph(4))
+        assert nx.has_eulerian_path(nx.hypercube_graph(6))
+
+    def test_has_eulerian_path_non_cyclic(self):
+        # Test graphs with Eulerian paths but no cycles return True.
+        assert nx.has_eulerian_path(nx.path_graph(4))
+        G = nx.path_graph(6, create_using=nx.DiGraph)
+        assert nx.has_eulerian_path(G)
+
+
+class TestFindPathStart:
+    def testfind_path_start(self):
+        find_path_start = nx.algorithms.euler._find_path_start
+        # Test digraphs return correct starting node.
+        G = nx.path_graph(6, create_using=nx.DiGraph)
+        assert find_path_start(G) == 0
+        edges = [(0, 1), (1, 2), (2, 0), (4, 0)]
+        assert find_path_start(nx.DiGraph(edges)) == 4
+
+        # Test graph with no Eulerian path return None.
+        edges = [(0, 1), (1, 2), (2, 3), (2, 4)]
+        assert find_path_start(nx.DiGraph(edges)) is None
+
+
+class TestEulerianPath:
+    def test_eulerian_path(self):
+        x = [(4, 0), (0, 1), (1, 2), (2, 0)]
+        for e1, e2 in zip(x, nx.eulerian_path(nx.DiGraph(x))):
+            assert e1 == e2
+
+
+class TestEulerize:
+    def test_disconnected(self):
+        with pytest.raises(nx.NetworkXError):
+            G = nx.from_edgelist([(0, 1), (2, 3)])
+            nx.eulerize(G)
+
+    def test_null_graph(self):
+        with pytest.raises(nx.NetworkXPointlessConcept):
+            nx.eulerize(nx.Graph())
+
+    def test_null_multigraph(self):
+        with pytest.raises(nx.NetworkXPointlessConcept):
+            nx.eulerize(nx.MultiGraph())
+
+    def test_on_empty_graph(self):
+        with pytest.raises(nx.NetworkXError):
+            nx.eulerize(nx.empty_graph(3))
+
+    def test_on_eulerian(self):
+        G = nx.cycle_graph(3)
+        H = nx.eulerize(G)
+        assert nx.is_isomorphic(G, H)
+
+    def test_on_eulerian_multigraph(self):
+        G = nx.MultiGraph(nx.cycle_graph(3))
+        G.add_edge(0, 1)
+        H = nx.eulerize(G)
+        assert nx.is_eulerian(H)
+
+    def test_on_complete_graph(self):
+        G = nx.complete_graph(4)
+        assert nx.is_eulerian(nx.eulerize(G))
+        assert nx.is_eulerian(nx.eulerize(nx.MultiGraph(G)))