Write tests for Graph

Author: YanWQ-monad

cyaron/tests/graph_test.py

@@ -0,0 +1,153 @@
+import unittest
+from cyaron import Graph
+
+
+class UnionFindSet:
+    def __init__(self, size):
+        self.father = [0] + [i + 1 for i in range(size)]
+
+    def get_father(self, node):
+        if self.father[node] == node:
+            return node
+        else:
+            self.father[node] = self.get_father(self.father[node])
+            return self.father[node]
+
+    def merge(self, l, r):
+        l = self.get_father(l)
+        r = self.get_father(r)
+        self.father[l] = r
+
+    def test_same(self, l, r):
+        return self.get_father(l) == self.get_father(r)
+
+
+def tarjan(graph, n):
+    def new_array(len, val=0):
+        return [val for _ in range(len+1)]
+
+    instack = new_array(n, False)
+    low = new_array(n)
+    dfn = new_array(n, 0)
+    stap = new_array(n)
+    belong = new_array(n)
+    cnt = bc = stop = 0
+
+    def dfs(cur):
+        nonlocal cnt, bc, stop
+        cnt += 1
+        dfn[cur] = low[cur] = cnt
+        instack[cur] = True
+        stap[stop] = cur
+        stop += 1
+
+        for v in graph.edges[cur]:
+            if dfn[v.end] == 0:
+                dfs(v.end)
+                low[cur] = min(low[cur], low[v.end])
+            elif instack[v.end]:
+                low[cur] = min(low[cur], dfn[v.end])
+
+        if dfn[cur] == low[cur]:
+            v = cur + 1 # set v != cur
+            bc += 1
+            while v != cur:
+                stop -= 1
+                v = stap[stop]
+                instack[v] = False
+                belong[v] = bc
+
+    for i in range(n):
+        if dfn[i+1] == 0:
+            dfs(i+1)
+
+    return belong
+
+
+class TestGraph(unittest.TestCase):
+
+    def test_self_loop(self):
+        graph_size = 20
+        for _ in range(20):
+            graph = Graph.graph(graph_size, int(graph_size*2), self_loop=True)
+            has_self_loop = max([e.start == e.end for e in graph.iterate_edges()])
+            if has_self_loop:
+                break
+        self.assertTrue(has_self_loop)
+
+        for _ in range(10):
+            graph = Graph.graph(graph_size, int(graph_size*2), self_loop=False)
+            self.assertFalse(max([e.start == e.end for e in graph.iterate_edges()]))
+
+    def test_repeated_edges(self):
+        graph_size = 20
+        for _ in range(20):
+            graph = Graph.graph(graph_size, int(graph_size*2), repeated_edges=True)
+            edges = [(e.start, e.end) for e in graph.iterate_edges()]
+            has_repeated_edges = len(edges) > len(set(edges))
+            if has_repeated_edges:
+                break
+        self.assertTrue(has_repeated_edges)
+
+        for _ in range(10):
+            graph = Graph.graph(graph_size, int(graph_size*2), repeated_edges=False)
+            edges = list(graph.iterate_edges())
+            self.assertEqual(len(edges), len(set(edges)))
+
+    def test_tree_connected(self):
+        graph_size = 20
+        for _ in range(20):
+            ufs = UnionFindSet(graph_size)
+            tree = Graph.tree(graph_size)
+            for edge in tree.iterate_edges():
+                ufs.merge(edge.start, edge.end)
+            for i in range(graph_size-1):
+                self.assertTrue(ufs.test_same(i+1, i+2))
+            
+
+    def test_DAG(self):
+        graph_size = 20
+        for _ in range(10): # test 10 times
+            ufs = UnionFindSet(graph_size)
+            graph = Graph.DAG(graph_size, int(graph_size*1.6), repeated_edges=False, self_loop=False, loop=True)
+
+            self.assertEqual(len(list(graph.iterate_edges())), int(graph_size*1.6))
+
+            for edge in graph.iterate_edges():
+                ufs.merge(edge.start, edge.end)
+            for i in range(graph_size-1):
+                self.assertTrue(ufs.test_same(i+1, i+2))
+
+    def test_DAG_without_loop(self):
+        graph_size = 20
+        for _ in range(10): # test 10 times
+            ufs = UnionFindSet(graph_size)
+            graph = Graph.DAG(graph_size, int(graph_size*1.6), repeated_edges=False, self_loop=False, loop=False)
+
+            self.assertEqual(len(list(graph.iterate_edges())), int(graph_size*1.6))
+
+            for edge in graph.iterate_edges():
+                ufs.merge(edge.start, edge.end)
+            for i in range(graph_size-1):
+                self.assertTrue(ufs.test_same(i+1, i+2))
+
+            belong = tarjan(graph, graph_size)
+            self.assertEqual(max(belong), graph_size)
+
+    def test_undirected_graph(self):
+        graph_size = 20
+        for _ in range(10): # test 10 times
+            ufs = UnionFindSet(graph_size)
+            graph = Graph.UDAG(graph_size, int(graph_size*1.6), repeated_edges=False, self_loop=False)
+
+            self.assertEqual(len(list(graph.iterate_edges())), int(graph_size*1.6))
+
+            for edge in graph.iterate_edges():
+                ufs.merge(edge.start, edge.end)
+            for i in range(graph_size-1):
+                self.assertTrue(ufs.test_same(i+1, i+2))
+
+    def test_DAG_boundary(self):
+        with self.assertRaises(Exception, msg="the number of edges of connected graph must more than the number of nodes - 1"):
+            Graph.DAG(8, 6)
+        Graph.DAG(8, 7)