from django.db.migrations.exceptions import ( CircularDependencyError, NodeNotFoundError, ) from django.db.migrations.graph import DummyNode, MigrationGraph, Node from django.test import SimpleTestCase class GraphTests(SimpleTestCase): """ 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): r""" 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 with self.assertRaises(CircularDependencyError): graph.ensure_not_cyclic() def test_circular_graph_2(self): graph = MigrationGraph() graph.add_node(('A', '0001'), None) graph.add_node(('C', '0001'), None) graph.add_node(('B', '0001'), None) graph.add_dependency('A.0001', ('A', '0001'), ('B', '0001')) graph.add_dependency('B.0001', ('B', '0001'), ('A', '0001')) graph.add_dependency('C.0001', ('C', '0001'), ('B', '0001')) with self.assertRaises(CircularDependencyError): graph.ensure_not_cyclic() def test_iterative_dfs(self): graph = MigrationGraph() root = ("app_a", "1") graph.add_node(root, None) expected = [root] for i in range(2, 750): 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) leaf = expected[-1] forwards_plan = graph.forwards_plan(leaf) self.assertEqual(expected, forwards_plan) backwards_plan = graph.backwards_plan(root) self.assertEqual(expected[::-1], backwards_plan) def test_iterative_dfs_complexity(self): """ In a graph with merge migrations, iterative_dfs() traverses each node only once even if there are multiple paths leading to it. """ n = 50 graph = MigrationGraph() for i in range(1, n + 1): graph.add_node(('app_a', str(i)), None) graph.add_node(('app_b', str(i)), None) graph.add_node(('app_c', str(i)), None) for i in range(1, n): graph.add_dependency(None, ('app_b', str(i)), ('app_a', str(i))) graph.add_dependency(None, ('app_c', str(i)), ('app_a', str(i))) graph.add_dependency(None, ('app_a', str(i + 1)), ('app_b', str(i))) graph.add_dependency(None, ('app_a', str(i + 1)), ('app_c', str(i))) plan = graph.forwards_plan(('app_a', str(n))) expected = [ (app, str(i)) for i in range(1, n) for app in ['app_a', 'app_c', 'app_b'] ] + [('app_a', str(n))] self.assertEqual(plan, expected) 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_validate_consistency_missing_parent(self): graph = MigrationGraph() graph.add_node(("app_a", "0001"), None) graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_b", "0002"), skip_validation=True) msg = "Migration app_a.0001 dependencies reference nonexistent parent node ('app_b', '0002')" with self.assertRaisesMessage(NodeNotFoundError, msg): graph.validate_consistency() def test_validate_consistency_missing_child(self): graph = MigrationGraph() graph.add_node(("app_b", "0002"), None) graph.add_dependency("app_b.0002", ("app_a", "0001"), ("app_b", "0002"), skip_validation=True) msg = "Migration app_b.0002 dependencies reference nonexistent child node ('app_a', '0001')" with self.assertRaisesMessage(NodeNotFoundError, msg): graph.validate_consistency() def test_validate_consistency_no_error(self): graph = MigrationGraph() graph.add_node(("app_a", "0001"), None) graph.add_node(("app_b", "0002"), None) graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_b", "0002"), skip_validation=True) graph.validate_consistency() def test_validate_consistency_dummy(self): """ validate_consistency() raises an error if there's an isolated dummy node. """ msg = "app_a.0001 (req'd by app_b.0002) is missing!" graph = MigrationGraph() graph.add_dummy_node( key=("app_a", "0001"), origin="app_b.0002", error_message=msg ) with self.assertRaisesMessage(NodeNotFoundError, msg): graph.validate_consistency() def test_remove_replaced_nodes(self): """ Replaced nodes are properly removed and dependencies remapped. """ # Add some dummy nodes to be replaced. graph = MigrationGraph() graph.add_dummy_node(key=("app_a", "0001"), origin="app_a.0002", error_message="BAD!") graph.add_dummy_node(key=("app_a", "0002"), origin="app_b.0001", error_message="BAD!") graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"), skip_validation=True) # Add some normal parent and child nodes to test dependency remapping. graph.add_node(("app_c", "0001"), None) graph.add_node(("app_b", "0001"), None) graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_c", "0001"), skip_validation=True) graph.add_dependency("app_b.0001", ("app_b", "0001"), ("app_a", "0002"), skip_validation=True) # Try replacing before replacement node exists. msg = ( "Unable to find replacement node ('app_a', '0001_squashed_0002'). It was either" " never added to the migration graph, or has been removed." ) with self.assertRaisesMessage(NodeNotFoundError, msg): graph.remove_replaced_nodes( replacement=("app_a", "0001_squashed_0002"), replaced=[("app_a", "0001"), ("app_a", "0002")] ) graph.add_node(("app_a", "0001_squashed_0002"), None) # Ensure `validate_consistency()` still raises an error at this stage. with self.assertRaisesMessage(NodeNotFoundError, "BAD!"): graph.validate_consistency() # Remove the dummy nodes. graph.remove_replaced_nodes( replacement=("app_a", "0001_squashed_0002"), replaced=[("app_a", "0001"), ("app_a", "0002")] ) # Ensure graph is now consistent and dependencies have been remapped graph.validate_consistency() parent_node = graph.node_map[("app_c", "0001")] replacement_node = graph.node_map[("app_a", "0001_squashed_0002")] child_node = graph.node_map[("app_b", "0001")] self.assertIn(parent_node, replacement_node.parents) self.assertIn(replacement_node, parent_node.children) self.assertIn(child_node, replacement_node.children) self.assertIn(replacement_node, child_node.parents) def test_remove_replacement_node(self): """ A replacement node is properly removed and child dependencies remapped. We assume parent dependencies are already correct. """ # Add some dummy nodes to be replaced. graph = MigrationGraph() graph.add_node(("app_a", "0001"), None) graph.add_node(("app_a", "0002"), None) graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001")) # Try removing replacement node before replacement node exists. msg = ( "Unable to remove replacement node ('app_a', '0001_squashed_0002'). It was" " either never added to the migration graph, or has been removed already." ) with self.assertRaisesMessage(NodeNotFoundError, msg): graph.remove_replacement_node( replacement=("app_a", "0001_squashed_0002"), replaced=[("app_a", "0001"), ("app_a", "0002")] ) graph.add_node(("app_a", "0001_squashed_0002"), None) # Add a child node to test dependency remapping. graph.add_node(("app_b", "0001"), None) graph.add_dependency("app_b.0001", ("app_b", "0001"), ("app_a", "0001_squashed_0002")) # Remove the replacement node. graph.remove_replacement_node( replacement=("app_a", "0001_squashed_0002"), replaced=[("app_a", "0001"), ("app_a", "0002")] ) # Ensure graph is consistent and child dependency has been remapped graph.validate_consistency() replaced_node = graph.node_map[("app_a", "0002")] child_node = graph.node_map[("app_b", "0001")] self.assertIn(child_node, replaced_node.children) self.assertIn(replaced_node, child_node.parents) # Ensure child dependency hasn't also gotten remapped to the other replaced node. other_replaced_node = graph.node_map[("app_a", "0001")] self.assertNotIn(child_node, other_replaced_node.children) self.assertNotIn(other_replaced_node, child_node.parents) 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 squashing 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.ensure_not_cyclic() def test_stringify(self): graph = MigrationGraph() self.assertEqual(str(graph), "Graph: 0 nodes, 0 edges") 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.0002", ("app_a", "0002"), ("app_a", "0001")) graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_a", "0002")) graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_b", "0002")) self.assertEqual(str(graph), "Graph: 5 nodes, 3 edges") self.assertEqual(repr(graph), "") class NodeTests(SimpleTestCase): def test_node_repr(self): node = Node(('app_a', '0001')) self.assertEqual(repr(node), "") def test_dummynode_repr(self): node = DummyNode( key=('app_a', '0001'), origin='app_a.0001', error_message='x is missing', ) self.assertEqual(repr(node), "")