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8e3c3be32d
Previous algo only worked if the first item was a part of the loop, and you would get an infinite loop otherwise (see test). To fix this, it was much easier to do a pre-pass. A bonus is that you now get an error message that actually helps you debug the dependency problem. Backport of ff3d746e8d8e8fbe6de287bd0f4c3a9fa23c18dc from master, with additional tests from c5def493d0993d65bf7d96f0a204006cbeaa6178
232 lines
9.2 KiB
Python
232 lines
9.2 KiB
Python
from django.test import TestCase
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from django.db.migrations.graph import MigrationGraph, CircularDependencyError
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class GraphTests(TestCase):
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"""
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Tests the digraph structure.
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"""
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def test_simple_graph(self):
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"""
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Tests a basic dependency graph:
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app_a: 0001 <-- 0002 <--- 0003 <-- 0004
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/
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app_b: 0001 <-- 0002 <-/
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"""
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# Build graph
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graph = MigrationGraph()
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graph.add_node(("app_a", "0001"), None)
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graph.add_node(("app_a", "0002"), None)
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graph.add_node(("app_a", "0003"), None)
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graph.add_node(("app_a", "0004"), None)
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graph.add_node(("app_b", "0001"), None)
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graph.add_node(("app_b", "0002"), None)
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graph.add_dependency("app_a.0004", ("app_a", "0004"), ("app_a", "0003"))
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graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_a", "0002"))
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graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"))
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graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_b", "0002"))
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graph.add_dependency("app_b.0002", ("app_b", "0002"), ("app_b", "0001"))
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# Test root migration case
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self.assertEqual(
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graph.forwards_plan(("app_a", "0001")),
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[('app_a', '0001')],
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)
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# Test branch B only
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self.assertEqual(
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graph.forwards_plan(("app_b", "0002")),
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[("app_b", "0001"), ("app_b", "0002")],
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)
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# Test whole graph
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self.assertEqual(
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graph.forwards_plan(("app_a", "0004")),
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[('app_b', '0001'), ('app_b', '0002'), ('app_a', '0001'), ('app_a', '0002'), ('app_a', '0003'), ('app_a', '0004')],
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)
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# Test reverse to b:0002
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self.assertEqual(
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graph.backwards_plan(("app_b", "0002")),
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[('app_a', '0004'), ('app_a', '0003'), ('app_b', '0002')],
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)
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# Test roots and leaves
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self.assertEqual(
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graph.root_nodes(),
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[('app_a', '0001'), ('app_b', '0001')],
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)
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self.assertEqual(
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graph.leaf_nodes(),
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[('app_a', '0004'), ('app_b', '0002')],
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)
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def test_complex_graph(self):
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"""
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Tests a complex dependency graph:
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app_a: 0001 <-- 0002 <--- 0003 <-- 0004
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\ \ / /
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app_b: 0001 <-\ 0002 <-X /
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\ \ /
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app_c: \ 0001 <-- 0002 <-
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"""
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# Build graph
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graph = MigrationGraph()
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graph.add_node(("app_a", "0001"), None)
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graph.add_node(("app_a", "0002"), None)
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graph.add_node(("app_a", "0003"), None)
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graph.add_node(("app_a", "0004"), None)
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graph.add_node(("app_b", "0001"), None)
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graph.add_node(("app_b", "0002"), None)
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graph.add_node(("app_c", "0001"), None)
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graph.add_node(("app_c", "0002"), None)
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graph.add_dependency("app_a.0004", ("app_a", "0004"), ("app_a", "0003"))
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graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_a", "0002"))
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graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"))
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graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_b", "0002"))
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graph.add_dependency("app_b.0002", ("app_b", "0002"), ("app_b", "0001"))
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graph.add_dependency("app_a.0004", ("app_a", "0004"), ("app_c", "0002"))
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graph.add_dependency("app_c.0002", ("app_c", "0002"), ("app_c", "0001"))
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graph.add_dependency("app_c.0001", ("app_c", "0001"), ("app_b", "0001"))
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graph.add_dependency("app_c.0002", ("app_c", "0002"), ("app_a", "0002"))
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# Test branch C only
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self.assertEqual(
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graph.forwards_plan(("app_c", "0002")),
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[('app_b', '0001'), ('app_c', '0001'), ('app_a', '0001'), ('app_a', '0002'), ('app_c', '0002')],
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)
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# Test whole graph
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self.assertEqual(
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graph.forwards_plan(("app_a", "0004")),
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[('app_b', '0001'), ('app_c', '0001'), ('app_a', '0001'), ('app_a', '0002'), ('app_c', '0002'), ('app_b', '0002'), ('app_a', '0003'), ('app_a', '0004')],
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)
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# Test reverse to b:0001
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self.assertEqual(
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graph.backwards_plan(("app_b", "0001")),
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[('app_a', '0004'), ('app_c', '0002'), ('app_c', '0001'), ('app_a', '0003'), ('app_b', '0002'), ('app_b', '0001')],
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)
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# Test roots and leaves
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self.assertEqual(
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graph.root_nodes(),
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[('app_a', '0001'), ('app_b', '0001'), ('app_c', '0001')],
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)
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self.assertEqual(
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graph.leaf_nodes(),
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[('app_a', '0004'), ('app_b', '0002'), ('app_c', '0002')],
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)
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def test_circular_graph(self):
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"""
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Tests a circular dependency graph.
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"""
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# Build graph
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graph = MigrationGraph()
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graph.add_node(("app_a", "0001"), None)
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graph.add_node(("app_a", "0002"), None)
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graph.add_node(("app_a", "0003"), None)
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graph.add_node(("app_b", "0001"), None)
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graph.add_node(("app_b", "0002"), None)
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graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_a", "0002"))
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graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"))
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graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_b", "0002"))
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graph.add_dependency("app_b.0002", ("app_b", "0002"), ("app_b", "0001"))
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graph.add_dependency("app_b.0001", ("app_b", "0001"), ("app_a", "0003"))
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# Test whole graph
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self.assertRaises(
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CircularDependencyError,
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graph.forwards_plan, ("app_a", "0003"),
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)
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def test_circular_graph_2(self):
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graph = MigrationGraph()
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graph.add_node(('A', '0001'), None)
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graph.add_node(('C', '0001'), None)
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graph.add_node(('B', '0001'), None)
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graph.add_dependency('A.0001', ('A', '0001'),('B', '0001'))
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graph.add_dependency('B.0001', ('B', '0001'),('A', '0001'))
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graph.add_dependency('C.0001', ('C', '0001'),('B', '0001'))
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self.assertRaises(
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CircularDependencyError,
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graph.forwards_plan, ('C', '0001')
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)
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def test_dfs(self):
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graph = MigrationGraph()
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root = ("app_a", "1")
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graph.add_node(root, None)
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expected = [root]
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for i in range(2, 1000):
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parent = ("app_a", str(i - 1))
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child = ("app_a", str(i))
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graph.add_node(child, None)
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graph.add_dependency(str(i), child, parent)
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expected.append(child)
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actual = graph.dfs(root, lambda x: graph.dependents.get(x, set()))
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self.assertEqual(expected[::-1], actual)
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def test_plan_invalid_node(self):
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"""
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Tests for forwards/backwards_plan of nonexistent node.
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"""
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graph = MigrationGraph()
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message = "Node ('app_b', '0001') not a valid node"
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with self.assertRaisesMessage(ValueError, message):
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graph.forwards_plan(("app_b", "0001"))
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with self.assertRaisesMessage(ValueError, message):
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graph.backwards_plan(("app_b", "0001"))
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def test_missing_parent_nodes(self):
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"""
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Tests for missing parent nodes.
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"""
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# Build graph
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graph = MigrationGraph()
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graph.add_node(("app_a", "0001"), None)
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graph.add_node(("app_a", "0002"), None)
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graph.add_node(("app_a", "0003"), None)
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graph.add_node(("app_b", "0001"), None)
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graph.add_dependency("app_a.0003", ("app_a", "0003"), ("app_a", "0002"))
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graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"))
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msg = "Migration app_a.0001 dependencies reference nonexistent parent node ('app_b', '0002')"
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with self.assertRaisesMessage(KeyError, msg):
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graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_b", "0002"))
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def test_missing_child_nodes(self):
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"""
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Tests for missing child nodes.
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"""
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# Build graph
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graph = MigrationGraph()
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graph.add_node(("app_a", "0001"), None)
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msg = "Migration app_a.0002 dependencies reference nonexistent child node ('app_a', '0002')"
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with self.assertRaisesMessage(KeyError, msg):
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graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"))
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def test_infinite_loop(self):
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"""
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Tests a complex dependency graph:
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app_a: 0001 <-
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\
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app_b: 0001 <- x 0002 <-
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/ \
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app_c: 0001<- <------------- x 0002
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And apply sqashing on app_c.
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"""
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graph = MigrationGraph()
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graph.add_node(("app_a", "0001"), None)
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graph.add_node(("app_b", "0001"), None)
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graph.add_node(("app_b", "0002"), None)
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graph.add_node(("app_c", "0001_squashed_0002"), None)
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graph.add_dependency("app_b.0001", ("app_b", "0001"), ("app_c", "0001_squashed_0002"))
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graph.add_dependency("app_b.0002", ("app_b", "0002"), ("app_a", "0001"))
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graph.add_dependency("app_b.0002", ("app_b", "0002"), ("app_b", "0001"))
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graph.add_dependency("app_c.0001_squashed_0002", ("app_c", "0001_squashed_0002"), ("app_b", "0002"))
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with self.assertRaises(CircularDependencyError):
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graph.forwards_plan(("app_c", "0001_squashed_0002"))
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