Add m-esr52 at 52.6.0

1 files changed, 644 insertions, 0 deletions

diff --git a/python/altgraph/altgraph_tests/test_graph.py b/python/altgraph/altgraph_tests/test_graph.py
new file mode 100644
index 000000000..553549f5a
--- /dev/null
+++ b/python/altgraph/altgraph_tests/test_graph.py
@@ -0,0 +1,644 @@
+import unittest
+
+from altgraph import GraphError
+from altgraph.Graph import Graph
+
+class TestGraph (unittest.TestCase):
+
+    def test_nodes(self):
+        graph = Graph()
+
+        self.assertEqual(graph.node_list(), [])
+
+        o1 = object()
+        o1b = object()
+        o2 = object()
+        graph.add_node(1, o1)
+        graph.add_node(1, o1b)
+        graph.add_node(2, o2)
+        graph.add_node(3)
+
+        self.assertRaises(TypeError, graph.add_node, [])
+
+        self.assertTrue(graph.node_data(1) is o1)
+        self.assertTrue(graph.node_data(2) is o2)
+        self.assertTrue(graph.node_data(3) is None)
+
+        self.assertTrue(1 in graph)
+        self.assertTrue(2 in graph)
+        self.assertTrue(3 in graph)
+
+        self.assertEqual(graph.number_of_nodes(), 3)
+        self.assertEqual(graph.number_of_hidden_nodes(), 0)
+        self.assertEqual(graph.hidden_node_list(), [])
+        self.assertEqual(list(sorted(graph)), [1, 2, 3])
+
+        graph.hide_node(1)
+        graph.hide_node(2)
+        graph.hide_node(3)
+
+
+        self.assertEqual(graph.number_of_nodes(), 0)
+        self.assertEqual(graph.number_of_hidden_nodes(), 3)
+        self.assertEqual(list(sorted(graph.hidden_node_list())), [1, 2, 3])
+
+        self.assertFalse(1 in graph)
+        self.assertFalse(2 in graph)
+        self.assertFalse(3 in graph)
+
+        graph.add_node(1)
+        self.assertFalse(1 in graph)
+
+        graph.restore_node(1)
+        self.assertTrue(1 in graph)
+        self.assertFalse(2 in graph)
+        self.assertFalse(3 in graph)
+
+        graph.restore_all_nodes()
+        self.assertTrue(1 in graph)
+        self.assertTrue(2 in graph)
+        self.assertTrue(3 in graph)
+
+        self.assertEqual(list(sorted(graph.node_list())), [1, 2, 3])
+
+        v = graph.describe_node(1)
+        self.assertEqual(v, (1, o1, [], []))
+
+    def test_edges(self):
+        graph = Graph()
+        graph.add_node(1)
+        graph.add_node(2)
+        graph.add_node(3)
+        graph.add_node(4)
+        graph.add_node(5)
+
+        self.assertTrue(isinstance(graph.edge_list(), list))
+
+        graph.add_edge(1, 2)
+        graph.add_edge(4, 5, 'a')
+
+        self.assertRaises(GraphError, graph.add_edge, 'a', 'b', create_nodes=False)
+
+        self.assertEqual(graph.number_of_hidden_edges(), 0)
+        self.assertEqual(graph.number_of_edges(), 2)
+        e = graph.edge_by_node(1, 2)
+        self.assertTrue(isinstance(e, int))
+        graph.hide_edge(e)
+        self.assertEqual(graph.number_of_hidden_edges(), 1)
+        self.assertEqual(graph.number_of_edges(), 1)
+        e2 = graph.edge_by_node(1, 2)
+        self.assertTrue(e2 is None)
+
+        graph.restore_edge(e)
+        e2 = graph.edge_by_node(1, 2)
+        self.assertEqual(e, e2)
+        self.assertEqual(graph.number_of_hidden_edges(), 0)
+
+        self.assertEqual(graph.number_of_edges(), 2)
+
+        e1 = graph.edge_by_node(1, 2)
+        e2 = graph.edge_by_node(4, 5)
+        graph.hide_edge(e1)
+        graph.hide_edge(e2)
+
+        self.assertEqual(graph.number_of_edges(), 0)
+        graph.restore_all_edges()
+        self.assertEqual(graph.number_of_edges(), 2)
+
+        self.assertEqual(graph.edge_by_id(e1), (1,2))
+        self.assertRaises(GraphError, graph.edge_by_id, (e1+1)*(e2+1)+1)
+
+        self.assertEqual(list(sorted(graph.edge_list())), [e1, e2])
+
+        self.assertEqual(graph.describe_edge(e1), (e1, 1, 1, 2))
+        self.assertEqual(graph.describe_edge(e2), (e2, 'a', 4, 5))
+
+        self.assertEqual(graph.edge_data(e1), 1)
+        self.assertEqual(graph.edge_data(e2), 'a')
+
+        self.assertEqual(graph.head(e2), 4)
+        self.assertEqual(graph.tail(e2), 5)
+
+        graph.add_edge(1, 3)
+        graph.add_edge(1, 5)
+        graph.add_edge(4, 1)
+
+        self.assertEqual(list(sorted(graph.out_nbrs(1))), [2, 3, 5])
+        self.assertEqual(list(sorted(graph.inc_nbrs(1))), [4])
+        self.assertEqual(list(sorted(graph.inc_nbrs(5))), [1, 4])
+        self.assertEqual(list(sorted(graph.all_nbrs(1))), [2, 3, 4, 5])
+
+        graph.add_edge(5, 1)
+        self.assertEqual(list(sorted(graph.all_nbrs(5))), [1, 4])
+
+        self.assertEqual(graph.out_degree(1), 3)
+        self.assertEqual(graph.inc_degree(2), 1)
+        self.assertEqual(graph.inc_degree(5), 2)
+        self.assertEqual(graph.all_degree(5), 3)
+
+        v = graph.out_edges(4)
+        self.assertTrue(isinstance(v, list))
+        self.assertEqual(graph.edge_by_id(v[0]), (4, 5))
+
+        v = graph.out_edges(1)
+        for e in v:
+            self.assertEqual(graph.edge_by_id(e)[0], 1)
+
+        v = graph.inc_edges(1)
+        self.assertTrue(isinstance(v, list))
+        self.assertEqual(graph.edge_by_id(v[0]), (4, 1))
+
+        v = graph.inc_edges(5)
+        for e in v:
+            self.assertEqual(graph.edge_by_id(e)[1], 5)
+
+        v = graph.all_edges(5)
+        for e in v:
+            self.assertTrue(graph.edge_by_id(e)[1] == 5 or graph.edge_by_id(e)[0] == 5)
+
+        e1 = graph.edge_by_node(1, 2)
+        self.assertTrue(isinstance(e1, int))
+        graph.hide_node(1)
+        self.assertRaises(GraphError, graph.edge_by_node, 1, 2)
+        graph.restore_node(1)
+        e2 = graph.edge_by_node(1, 2)
+        self.assertEqual(e1, e2)
+
+
+
+    def test_toposort(self):
+        graph = Graph()
+        graph.add_node(1)
+        graph.add_node(2)
+        graph.add_node(3)
+        graph.add_node(4)
+        graph.add_node(5)
+
+        graph.add_edge(1, 2)
+        graph.add_edge(1, 3)
+        graph.add_edge(2, 4)
+        graph.add_edge(3, 5)
+
+        ok, result = graph.forw_topo_sort()
+        self.assertTrue(ok)
+        for idx in range(1, 6):
+            self.assertTrue(idx in result)
+
+        self.assertTrue(result.index(1) < result.index(2))
+        self.assertTrue(result.index(1) < result.index(3))
+        self.assertTrue(result.index(2) < result.index(4))
+        self.assertTrue(result.index(3) < result.index(5))
+
+        ok, result = graph.back_topo_sort()
+        self.assertTrue(ok)
+        for idx in range(1, 6):
+            self.assertTrue(idx in result)
+        self.assertTrue(result.index(2) < result.index(1))
+        self.assertTrue(result.index(3) < result.index(1))
+        self.assertTrue(result.index(4) < result.index(2))
+        self.assertTrue(result.index(5) < result.index(3))
+
+
+        # Same graph as before, but with edges
+        # reversed, which means we should get
+        # the same results as before if using
+        # back_topo_sort rather than forw_topo_sort
+        # (and v.v.)
+
+        graph = Graph()
+        graph.add_node(1)
+        graph.add_node(2)
+        graph.add_node(3)
+        graph.add_node(4)
+        graph.add_node(5)
+
+        graph.add_edge(2, 1)
+        graph.add_edge(3, 1)
+        graph.add_edge(4, 2)
+        graph.add_edge(5, 3)
+
+        ok, result = graph.back_topo_sort()
+        self.assertTrue(ok)
+        for idx in range(1, 6):
+            self.assertTrue(idx in result)
+
+        self.assertTrue(result.index(1) < result.index(2))
+        self.assertTrue(result.index(1) < result.index(3))
+        self.assertTrue(result.index(2) < result.index(4))
+        self.assertTrue(result.index(3) < result.index(5))
+
+        ok, result = graph.forw_topo_sort()
+        self.assertTrue(ok)
+        for idx in range(1, 6):
+            self.assertTrue(idx in result)
+        self.assertTrue(result.index(2) < result.index(1))
+        self.assertTrue(result.index(3) < result.index(1))
+        self.assertTrue(result.index(4) < result.index(2))
+        self.assertTrue(result.index(5) < result.index(3))
+
+
+        # Create a cycle
+        graph.add_edge(1, 5)
+        ok, result = graph.forw_topo_sort()
+        self.assertFalse(ok)
+        ok, result = graph.back_topo_sort()
+        self.assertFalse(ok)
+
+    def test_bfs_subgraph(self):
+        graph = Graph()
+        graph.add_edge(1, 2)
+        graph.add_edge(1, 4)
+        graph.add_edge(2, 4)
+        graph.add_edge(4, 8)
+        graph.add_edge(4, 9)
+        graph.add_edge(4, 10)
+        graph.add_edge(8, 10)
+
+        subgraph = graph.forw_bfs_subgraph(10)
+        self.assertTrue(isinstance(subgraph, Graph))
+        self.assertEqual(subgraph.number_of_nodes(), 1)
+        self.assertTrue(10 in subgraph)
+        self.assertEqual(subgraph.number_of_edges(), 0)
+
+        subgraph = graph.forw_bfs_subgraph(4)
+        self.assertTrue(isinstance(subgraph, Graph))
+        self.assertEqual(subgraph.number_of_nodes(), 4)
+        self.assertTrue(4 in subgraph)
+        self.assertTrue(8 in subgraph)
+        self.assertTrue(9 in subgraph)
+        self.assertTrue(10 in subgraph)
+        self.assertEqual(subgraph.number_of_edges(), 4)
+        e = subgraph.edge_by_node(4, 8)
+        e = subgraph.edge_by_node(4, 9)
+        e = subgraph.edge_by_node(4, 10)
+        e = subgraph.edge_by_node(8, 10)
+
+        # same graph as before, but switch around
+        # edges. This results in the same test results
+        # but now for back_bfs_subgraph rather than
+        # forw_bfs_subgraph
+
+        graph = Graph()
+        graph.add_edge(2, 1)
+        graph.add_edge(4, 1)
+        graph.add_edge(4, 2)
+        graph.add_edge(8, 4)
+        graph.add_edge(9, 4)
+        graph.add_edge(10, 4)
+        graph.add_edge(10, 8)
+
+        subgraph = graph.back_bfs_subgraph(10)
+        self.assertTrue(isinstance(subgraph, Graph))
+        self.assertEqual(subgraph.number_of_nodes(), 1)
+        self.assertTrue(10 in subgraph)
+        self.assertEqual(subgraph.number_of_edges(), 0)
+
+        subgraph = graph.back_bfs_subgraph(4)
+        self.assertTrue(isinstance(subgraph, Graph))
+        self.assertEqual(subgraph.number_of_nodes(), 4)
+        self.assertTrue(4 in subgraph)
+        self.assertTrue(8 in subgraph)
+        self.assertTrue(9 in subgraph)
+        self.assertTrue(10 in subgraph)
+        self.assertEqual(subgraph.number_of_edges(), 4)
+        e = subgraph.edge_by_node(4, 8)
+        e = subgraph.edge_by_node(4, 9)
+        e = subgraph.edge_by_node(4, 10)
+        e = subgraph.edge_by_node(8, 10)
+
+    def test_iterdfs(self):
+        graph = Graph()
+        graph.add_edge("1", "1.1")
+        graph.add_edge("1", "1.2")
+        graph.add_edge("1", "1.3")
+        graph.add_edge("1.1", "1.1.1")
+        graph.add_edge("1.1", "1.1.2")
+        graph.add_edge("1.2", "1.2.1")
+        graph.add_edge("1.2", "1.2.2")
+        graph.add_edge("1.2.2", "1.2.2.1")
+        graph.add_edge("1.2.2", "1.2.2.2")
+        graph.add_edge("1.2.2", "1.2.2.3")
+
+        result = list(graph.iterdfs("1"))
+        self.assertEqual(result, [
+            '1', '1.3', '1.2', '1.2.2', '1.2.2.3', '1.2.2.2',
+            '1.2.2.1', '1.2.1', '1.1', '1.1.2', '1.1.1'
+        ])
+        result = list(graph.iterdfs("1", "1.2.1"))
+        self.assertEqual(result, [
+            '1', '1.3', '1.2', '1.2.2', '1.2.2.3', '1.2.2.2',
+            '1.2.2.1', '1.2.1'
+        ])
+
+        result = graph.forw_dfs("1")
+        self.assertEqual(result, [
+            '1', '1.3', '1.2', '1.2.2', '1.2.2.3', '1.2.2.2',
+            '1.2.2.1', '1.2.1', '1.1', '1.1.2', '1.1.1'
+        ])
+        result = graph.forw_dfs("1", "1.2.1")
+        self.assertEqual(result, [
+            '1', '1.3', '1.2', '1.2.2', '1.2.2.3', '1.2.2.2',
+            '1.2.2.1', '1.2.1'
+        ])
+
+        graph = Graph()
+        graph.add_edge("1.1", "1")
+        graph.add_edge("1.2", "1")
+        graph.add_edge("1.3", "1")
+        graph.add_edge("1.1.1", "1.1")
+        graph.add_edge("1.1.2", "1.1")
+        graph.add_edge("1.2.1", "1.2")
+        graph.add_edge("1.2.2", "1.2")
+        graph.add_edge("1.2.2.1", "1.2.2")
+        graph.add_edge("1.2.2.2", "1.2.2")
+        graph.add_edge("1.2.2.3", "1.2.2")
+
+        result = list(graph.iterdfs("1", forward=False))
+        self.assertEqual(result, [
+            '1', '1.3', '1.2', '1.2.2', '1.2.2.3', '1.2.2.2',
+            '1.2.2.1', '1.2.1', '1.1', '1.1.2', '1.1.1'
+        ])
+        result = list(graph.iterdfs("1", "1.2.1", forward=False))
+        self.assertEqual(result, [
+            '1', '1.3', '1.2', '1.2.2', '1.2.2.3', '1.2.2.2',
+            '1.2.2.1', '1.2.1'
+        ])
+        result = graph.back_dfs("1")
+        self.assertEqual(result, [
+            '1', '1.3', '1.2', '1.2.2', '1.2.2.3', '1.2.2.2',
+            '1.2.2.1', '1.2.1', '1.1', '1.1.2', '1.1.1'
+        ])
+        result = graph.back_dfs("1", "1.2.1")
+        self.assertEqual(result, [
+            '1', '1.3', '1.2', '1.2.2', '1.2.2.3', '1.2.2.2',
+            '1.2.2.1', '1.2.1'
+        ])
+
+
+        # Introduce cyle:
+        graph.add_edge("1", "1.2")
+        result = list(graph.iterdfs("1", forward=False))
+        self.assertEqual(result, [
+            '1', '1.3', '1.2', '1.2.2', '1.2.2.3', '1.2.2.2',
+            '1.2.2.1', '1.2.1', '1.1', '1.1.2', '1.1.1'
+        ])
+
+        result = graph.back_dfs("1")
+        self.assertEqual(result, [
+            '1', '1.3', '1.2', '1.2.2', '1.2.2.3', '1.2.2.2',
+            '1.2.2.1', '1.2.1', '1.1', '1.1.2', '1.1.1'
+        ])
+
+
+    def test_iterdata(self):
+        graph = Graph()
+        graph.add_node("1", "I")
+        graph.add_node("1.1", "I.I")
+        graph.add_node("1.2", "I.II")
+        graph.add_node("1.3", "I.III")
+        graph.add_node("1.1.1", "I.I.I")
+        graph.add_node("1.1.2", "I.I.II")
+        graph.add_node("1.2.1", "I.II.I")
+        graph.add_node("1.2.2", "I.II.II")
+        graph.add_node("1.2.2.1", "I.II.II.I")
+        graph.add_node("1.2.2.2", "I.II.II.II")
+        graph.add_node("1.2.2.3", "I.II.II.III")
+
+        graph.add_edge("1", "1.1")
+        graph.add_edge("1", "1.2")
+        graph.add_edge("1", "1.3")
+        graph.add_edge("1.1", "1.1.1")
+        graph.add_edge("1.1", "1.1.2")
+        graph.add_edge("1.2", "1.2.1")
+        graph.add_edge("1.2", "1.2.2")
+        graph.add_edge("1.2.2", "1.2.2.1")
+        graph.add_edge("1.2.2", "1.2.2.2")
+        graph.add_edge("1.2.2", "1.2.2.3")
+
+        result = list(graph.iterdata("1", forward=True))
+        self.assertEqual(result, [
+            'I', 'I.III', 'I.II', 'I.II.II', 'I.II.II.III', 'I.II.II.II',
+            'I.II.II.I', 'I.II.I', 'I.I', 'I.I.II', 'I.I.I'
+        ])
+
+        result = list(graph.iterdata("1", end="1.2.1", forward=True))
+        self.assertEqual(result, [
+            'I', 'I.III', 'I.II', 'I.II.II', 'I.II.II.III', 'I.II.II.II',
+            'I.II.II.I', 'I.II.I'
+        ])
+
+        result = list(graph.iterdata("1", condition=lambda n: len(n) < 6, forward=True))
+        self.assertEqual(result, [
+            'I', 'I.III', 'I.II',
+            'I.I', 'I.I.I'
+        ])
+
+
+        # And the revese option:
+        graph = Graph()
+        graph.add_node("1", "I")
+        graph.add_node("1.1", "I.I")
+        graph.add_node("1.2", "I.II")
+        graph.add_node("1.3", "I.III")
+        graph.add_node("1.1.1", "I.I.I")
+        graph.add_node("1.1.2", "I.I.II")
+        graph.add_node("1.2.1", "I.II.I")
+        graph.add_node("1.2.2", "I.II.II")
+        graph.add_node("1.2.2.1", "I.II.II.I")
+        graph.add_node("1.2.2.2", "I.II.II.II")
+        graph.add_node("1.2.2.3", "I.II.II.III")
+
+        graph.add_edge("1.1", "1")
+        graph.add_edge("1.2", "1")
+        graph.add_edge("1.3", "1")
+        graph.add_edge("1.1.1", "1.1")
+        graph.add_edge("1.1.2", "1.1")
+        graph.add_edge("1.2.1", "1.2")
+        graph.add_edge("1.2.2", "1.2")
+        graph.add_edge("1.2.2.1", "1.2.2")
+        graph.add_edge("1.2.2.2", "1.2.2")
+        graph.add_edge("1.2.2.3", "1.2.2")
+
+        result = list(graph.iterdata("1", forward=False))
+        self.assertEqual(result, [
+            'I', 'I.III', 'I.II', 'I.II.II', 'I.II.II.III', 'I.II.II.II',
+            'I.II.II.I', 'I.II.I', 'I.I', 'I.I.II', 'I.I.I'
+        ])
+
+        result = list(graph.iterdata("1", end="1.2.1", forward=False))
+        self.assertEqual(result, [
+            'I', 'I.III', 'I.II', 'I.II.II', 'I.II.II.III', 'I.II.II.II',
+            'I.II.II.I', 'I.II.I'
+        ])
+
+        result = list(graph.iterdata("1", condition=lambda n: len(n) < 6, forward=False))
+        self.assertEqual(result, [
+            'I', 'I.III', 'I.II',
+            'I.I', 'I.I.I'
+        ])
+
+    def test_bfs(self):
+        graph = Graph()
+        graph.add_edge("1", "1.1")
+        graph.add_edge("1.1", "1.1.1")
+        graph.add_edge("1.1", "1.1.2")
+        graph.add_edge("1.1.2", "1.1.2.1")
+        graph.add_edge("1.1.2", "1.1.2.2")
+        graph.add_edge("1", "1.2")
+        graph.add_edge("1", "1.3")
+        graph.add_edge("1.2", "1.2.1")
+
+        self.assertEqual(graph.forw_bfs("1"),
+                ['1', '1.1', '1.2', '1.3', '1.1.1', '1.1.2', '1.2.1', '1.1.2.1', '1.1.2.2'])
+        self.assertEqual(graph.forw_bfs("1", "1.1.1"),
+                ['1', '1.1', '1.2', '1.3', '1.1.1'])
+
+
+        # And the "reverse" graph
+        graph = Graph()
+        graph.add_edge("1.1", "1")
+        graph.add_edge("1.1.1", "1.1")
+        graph.add_edge("1.1.2", "1.1")
+        graph.add_edge("1.1.2.1", "1.1.2")
+        graph.add_edge("1.1.2.2", "1.1.2")
+        graph.add_edge("1.2", "1")
+        graph.add_edge("1.3", "1")
+        graph.add_edge("1.2.1", "1.2")
+
+        self.assertEqual(graph.back_bfs("1"),
+                ['1', '1.1', '1.2', '1.3', '1.1.1', '1.1.2', '1.2.1', '1.1.2.1', '1.1.2.2'])
+        self.assertEqual(graph.back_bfs("1", "1.1.1"),
+                ['1', '1.1', '1.2', '1.3', '1.1.1'])
+
+
+
+        # check cycle handling
+        graph.add_edge("1", "1.2.1")
+        self.assertEqual(graph.back_bfs("1"),
+                ['1', '1.1', '1.2', '1.3', '1.1.1', '1.1.2', '1.2.1', '1.1.2.1', '1.1.2.2'])
+
+
+    def test_connected(self):
+        graph = Graph()
+        graph.add_node(1)
+        graph.add_node(2)
+        graph.add_node(3)
+        graph.add_node(4)
+
+        self.assertFalse(graph.connected())
+
+        graph.add_edge(1, 2)
+        graph.add_edge(3, 4)
+        self.assertFalse(graph.connected())
+
+        graph.add_edge(2, 3)
+        graph.add_edge(4, 1)
+        self.assertTrue(graph.connected())
+
+    def test_edges_complex(self):
+        g = Graph()
+        g.add_edge(1, 2)
+        e = g.edge_by_node(1,2)
+        g.hide_edge(e)
+        g.hide_node(2)
+        self.assertRaises(GraphError, g.restore_edge, e)
+
+        g.restore_all_edges()
+        self.assertRaises(GraphError, g.edge_by_id, e)
+
+    def test_clust_coef(self):
+        g = Graph()
+        g.add_edge(1, 2)
+        g.add_edge(1, 3)
+        g.add_edge(1, 4)
+        self.assertEqual(g.clust_coef(1), 0)
+
+        g.add_edge(2, 5)
+        g.add_edge(3, 5)
+        g.add_edge(4, 5)
+        self.assertEqual(g.clust_coef(1), 0)
+
+        g.add_edge(2, 3)
+        self.assertEqual(g.clust_coef(1), 1./6)
+        g.add_edge(2, 4)
+        self.assertEqual(g.clust_coef(1), 2./6)
+        g.add_edge(4, 2)
+        self.assertEqual(g.clust_coef(1), 3./6)
+
+        g.add_edge(2, 3)
+        g.add_edge(2, 4)
+        g.add_edge(3, 4)
+        g.add_edge(3, 2)
+        g.add_edge(4, 2)
+        g.add_edge(4, 3)
+        self.assertEqual(g.clust_coef(1), 1)
+
+
+    def test_get_hops(self):
+        graph = Graph()
+        graph.add_edge(1, 2)
+        graph.add_edge(1, 3)
+        graph.add_edge(2, 4)
+        graph.add_edge(4, 5)
+        graph.add_edge(5, 7)
+        graph.add_edge(7, 8)
+
+        self.assertEqual(graph.get_hops(1),
+            [(1, 0), (2, 1), (3, 1), (4, 2), (5, 3), (7, 4), (8, 5)])
+
+        self.assertEqual(graph.get_hops(1, 5),
+            [(1, 0), (2, 1), (3, 1), (4, 2), (5, 3)])
+
+        graph.add_edge(5, 1)
+        graph.add_edge(7, 1)
+        graph.add_edge(7, 4)
+
+        self.assertEqual(graph.get_hops(1),
+            [(1, 0), (2, 1), (3, 1), (4, 2), (5, 3), (7, 4), (8, 5)])
+
+        # And the reverse graph
+        graph = Graph()
+        graph.add_edge(2, 1)
+        graph.add_edge(3, 1)
+        graph.add_edge(4, 2)
+        graph.add_edge(5, 4)
+        graph.add_edge(7, 5)
+        graph.add_edge(8, 7)
+
+        self.assertEqual(graph.get_hops(1, forward=False),
+            [(1, 0), (2, 1), (3, 1), (4, 2), (5, 3), (7, 4), (8, 5)])
+
+        self.assertEqual(graph.get_hops(1, 5, forward=False),
+            [(1, 0), (2, 1), (3, 1), (4, 2), (5, 3)])
+
+        graph.add_edge(1, 5)
+        graph.add_edge(1, 7)
+        graph.add_edge(4, 7)
+
+        self.assertEqual(graph.get_hops(1, forward=False),
+            [(1, 0), (2, 1), (3, 1), (4, 2), (5, 3), (7, 4), (8, 5)])
+
+
+    def test_constructor(self):
+        graph = Graph(iter([
+                (1, 2),
+                (2, 3, 'a'),
+                (1, 3),
+                (3, 4),
+            ]))
+        self.assertEqual(graph.number_of_nodes(), 4)
+        self.assertEqual(graph.number_of_edges(), 4)
+        try:
+            graph.edge_by_node(1,2)
+            graph.edge_by_node(2,3)
+            graph.edge_by_node(1,3)
+            graph.edge_by_node(3,4)
+        except GraphError:
+            self.fail("Incorrect graph")
+
+        self.assertEqual(graph.edge_data(graph.edge_by_node(2, 3)), 'a')
+
+        self.assertRaises(GraphError, Graph, [(1,2,3,4)])
+
+if __name__ == "__main__": # pragma: no cover
+    unittest.main()