from django.test import TestCase from django.db.migrations.graph import CircularDependencyError, MigrationGraph, NodeNotFoundError class GraphTests(TestCase): """ Tests the digraph structure. """ def test_simple_graph(self): """ Tests a basic dependency graph: app_a: 0001 <-- 0002 <--- 0003 <-- 0004 / app_b: 0001 <-- 0002 <-/ """ # Build graph graph = MigrationGraph() graph.add_node(("app_a", "0001"), None) graph.add_node(("app_a", "0002"), None) graph.add_node(("app_a", "0003"), None) graph.add_node(("app_a", "0004"), None) graph.add_node(("app_b", "0001"), None) graph.add_node(("app_b", "0002"), None) graph.add_dependency("app_a.0004", ("app_a", "0004"), ("app_a", "0003")) graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_a", "0002")) graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001")) graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_b", "0002")) graph.add_dependency("app_b.0002", ("app_b", "0002"), ("app_b", "0001")) # Test root migration case self.assertEqual( graph.forwards_plan(("app_a", "0001")), [('app_a', '0001')], ) # Test branch B only self.assertEqual( graph.forwards_plan(("app_b", "0002")), [("app_b", "0001"), ("app_b", "0002")], ) # Test whole graph self.assertEqual( graph.forwards_plan(("app_a", "0004")), [('app_b', '0001'), ('app_b', '0002'), ('app_a', '0001'), ('app_a', '0002'), ('app_a', '0003'), ('app_a', '0004')], ) # Test reverse to b:0002 self.assertEqual( graph.backwards_plan(("app_b", "0002")), [('app_a', '0004'), ('app_a', '0003'), ('app_b', '0002')], ) # Test roots and leaves self.assertEqual( graph.root_nodes(), [('app_a', '0001'), ('app_b', '0001')], ) self.assertEqual( graph.leaf_nodes(), [('app_a', '0004'), ('app_b', '0002')], ) def test_complex_graph(self): """ Tests a complex dependency graph: app_a: 0001 <-- 0002 <--- 0003 <-- 0004 \ \ / / app_b: 0001 <-\ 0002 <-X / \ \ / app_c: \ 0001 <-- 0002 <- """ # Build graph graph = MigrationGraph() graph.add_node(("app_a", "0001"), None) graph.add_node(("app_a", "0002"), None) graph.add_node(("app_a", "0003"), None) graph.add_node(("app_a", "0004"), None) graph.add_node(("app_b", "0001"), None) graph.add_node(("app_b", "0002"), None) graph.add_node(("app_c", "0001"), None) graph.add_node(("app_c", "0002"), None) graph.add_dependency("app_a.0004", ("app_a", "0004"), ("app_a", "0003")) graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_a", "0002")) graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001")) graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_b", "0002")) graph.add_dependency("app_b.0002", ("app_b", "0002"), ("app_b", "0001")) graph.add_dependency("app_a.0004", ("app_a", "0004"), ("app_c", "0002")) graph.add_dependency("app_c.0002", ("app_c", "0002"), ("app_c", "0001")) graph.add_dependency("app_c.0001", ("app_c", "0001"), ("app_b", "0001")) graph.add_dependency("app_c.0002", ("app_c", "0002"), ("app_a", "0002")) # Test branch C only self.assertEqual( graph.forwards_plan(("app_c", "0002")), [('app_b', '0001'), ('app_c', '0001'), ('app_a', '0001'), ('app_a', '0002'), ('app_c', '0002')], ) # Test whole graph self.assertEqual( graph.forwards_plan(("app_a", "0004")), [('app_b', '0001'), ('app_c', '0001'), ('app_a', '0001'), ('app_a', '0002'), ('app_c', '0002'), ('app_b', '0002'), ('app_a', '0003'), ('app_a', '0004')], ) # Test reverse to b:0001 self.assertEqual( graph.backwards_plan(("app_b", "0001")), [('app_a', '0004'), ('app_c', '0002'), ('app_c', '0001'), ('app_a', '0003'), ('app_b', '0002'), ('app_b', '0001')], ) # Test roots and leaves self.assertEqual( graph.root_nodes(), [('app_a', '0001'), ('app_b', '0001'), ('app_c', '0001')], ) self.assertEqual( graph.leaf_nodes(), [('app_a', '0004'), ('app_b', '0002'), ('app_c', '0002')], ) def test_circular_graph(self): """ Tests a circular dependency graph. """ # Build graph graph = MigrationGraph() graph.add_node(("app_a", "0001"), None) graph.add_node(("app_a", "0002"), None) graph.add_node(("app_a", "0003"), None) graph.add_node(("app_b", "0001"), None) graph.add_node(("app_b", "0002"), None) graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_a", "0002")) graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001")) graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_b", "0002")) graph.add_dependency("app_b.0002", ("app_b", "0002"), ("app_b", "0001")) graph.add_dependency("app_b.0001", ("app_b", "0001"), ("app_a", "0003")) # Test whole graph self.assertRaises( CircularDependencyError, graph.forwards_plan, ("app_a", "0003"), ) def test_dfs(self): graph = MigrationGraph() root = ("app_a", "1") graph.add_node(root, None) expected = [root] for i in range(2, 1000): parent = ("app_a", str(i - 1)) child = ("app_a", str(i)) graph.add_node(child, None) graph.add_dependency(str(i), child, parent) expected.append(child) actual = graph.dfs(root, lambda x: graph.dependents.get(x, set())) self.assertEqual(expected[::-1], actual) def test_plan_invalid_node(self): """ Tests for forwards/backwards_plan of nonexistent node. """ graph = MigrationGraph() message = "Node ('app_b', '0001') not a valid node" with self.assertRaisesMessage(NodeNotFoundError, message): graph.forwards_plan(("app_b", "0001")) with self.assertRaisesMessage(NodeNotFoundError, message): graph.backwards_plan(("app_b", "0001")) def test_missing_parent_nodes(self): """ Tests for missing parent nodes. """ # Build graph graph = MigrationGraph() graph.add_node(("app_a", "0001"), None) graph.add_node(("app_a", "0002"), None) graph.add_node(("app_a", "0003"), None) graph.add_node(("app_b", "0001"), None) graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_a", "0002")) graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001")) msg = "Migration app_a.0001 dependencies reference nonexistent parent node ('app_b', '0002')" with self.assertRaisesMessage(NodeNotFoundError, msg): graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_b", "0002")) def test_missing_child_nodes(self): """ Tests for missing child nodes. """ # Build graph graph = MigrationGraph() graph.add_node(("app_a", "0001"), None) msg = "Migration app_a.0002 dependencies reference nonexistent child node ('app_a', '0002')" with self.assertRaisesMessage(NodeNotFoundError, msg): graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001")) def test_infinite_loop(self): """ Tests a complex dependency graph: app_a: 0001 <- \ app_b: 0001 <- x 0002 <- / \ app_c: 0001<- <------------- x 0002 And apply sqashing on app_c. """ graph = MigrationGraph() graph.add_node(("app_a", "0001"), None) graph.add_node(("app_b", "0001"), None) graph.add_node(("app_b", "0002"), None) graph.add_node(("app_c", "0001_squashed_0002"), None) graph.add_dependency("app_b.0001", ("app_b", "0001"), ("app_c", "0001_squashed_0002")) graph.add_dependency("app_b.0002", ("app_b", "0002"), ("app_a", "0001")) graph.add_dependency("app_b.0002", ("app_b", "0002"), ("app_b", "0001")) graph.add_dependency("app_c.0001_squashed_0002", ("app_c", "0001_squashed_0002"), ("app_b", "0002")) with self.assertRaises(CircularDependencyError): graph.forwards_plan(("app_c", "0001_squashed_0002"))