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			419 lines
		
	
	
	
		
			18 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			419 lines
		
	
	
	
		
			18 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
from django.db.migrations.exceptions import (
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    CircularDependencyError, NodeNotFoundError,
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)
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from django.db.migrations.graph import DummyNode, MigrationGraph, Node
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from django.test import SimpleTestCase
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class GraphTests(SimpleTestCase):
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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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            [
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                ('app_b', '0001'), ('app_b', '0002'), ('app_a', '0001'),
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                ('app_a', '0002'), ('app_a', '0003'), ('app_a', '0004'),
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            ],
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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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        r"""
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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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            [
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                ('app_b', '0001'), ('app_c', '0001'), ('app_a', '0001'),
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                ('app_a', '0002'), ('app_c', '0002'), ('app_b', '0002'),
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                ('app_a', '0003'), ('app_a', '0004'),
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            ],
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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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            [
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                ('app_a', '0004'), ('app_c', '0002'), ('app_c', '0001'),
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                ('app_a', '0003'), ('app_b', '0002'), ('app_b', '0001'),
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            ],
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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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        with self.assertRaises(CircularDependencyError):
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            graph.ensure_not_cyclic()
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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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        with self.assertRaises(CircularDependencyError):
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            graph.ensure_not_cyclic()
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    def test_iterative_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, 750):
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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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        leaf = expected[-1]
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        forwards_plan = graph.forwards_plan(leaf)
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        self.assertEqual(expected, forwards_plan)
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        backwards_plan = graph.backwards_plan(root)
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        self.assertEqual(expected[::-1], backwards_plan)
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    def test_iterative_dfs_complexity(self):
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        """
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        In a graph with merge migrations, iterative_dfs() traverses each node
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        only once even if there are multiple paths leading to it.
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        """
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        n = 50
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        graph = MigrationGraph()
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        for i in range(1, n + 1):
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            graph.add_node(('app_a', str(i)), None)
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            graph.add_node(('app_b', str(i)), None)
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            graph.add_node(('app_c', str(i)), None)
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        for i in range(1, n):
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            graph.add_dependency(None, ('app_b', str(i)), ('app_a', str(i)))
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            graph.add_dependency(None, ('app_c', str(i)), ('app_a', str(i)))
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            graph.add_dependency(None, ('app_a', str(i + 1)), ('app_b', str(i)))
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            graph.add_dependency(None, ('app_a', str(i + 1)), ('app_c', str(i)))
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        plan = graph.forwards_plan(('app_a', str(n)))
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        expected = [
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            (app, str(i))
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            for i in range(1, n)
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            for app in ['app_a', 'app_c', 'app_b']
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        ] + [('app_a', str(n))]
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        self.assertEqual(plan, expected)
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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(NodeNotFoundError, message):
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            graph.forwards_plan(("app_b", "0001"))
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        with self.assertRaisesMessage(NodeNotFoundError, 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(NodeNotFoundError, 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(NodeNotFoundError, msg):
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            graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"))
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    def test_validate_consistency_missing_parent(self):
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        graph = MigrationGraph()
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        graph.add_node(("app_a", "0001"), None)
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        graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_b", "0002"), skip_validation=True)
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        msg = "Migration app_a.0001 dependencies reference nonexistent parent node ('app_b', '0002')"
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        with self.assertRaisesMessage(NodeNotFoundError, msg):
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            graph.validate_consistency()
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    def test_validate_consistency_missing_child(self):
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        graph = MigrationGraph()
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        graph.add_node(("app_b", "0002"), None)
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        graph.add_dependency("app_b.0002", ("app_a", "0001"), ("app_b", "0002"), skip_validation=True)
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        msg = "Migration app_b.0002 dependencies reference nonexistent child node ('app_a', '0001')"
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        with self.assertRaisesMessage(NodeNotFoundError, msg):
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            graph.validate_consistency()
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    def test_validate_consistency_no_error(self):
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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", "0002"), None)
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        graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_b", "0002"), skip_validation=True)
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        graph.validate_consistency()
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    def test_validate_consistency_dummy(self):
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        """
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        validate_consistency() raises an error if there's an isolated dummy
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        node.
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        """
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        msg = "app_a.0001 (req'd by app_b.0002) is missing!"
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        graph = MigrationGraph()
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        graph.add_dummy_node(
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            key=("app_a", "0001"),
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            origin="app_b.0002",
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            error_message=msg
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        )
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        with self.assertRaisesMessage(NodeNotFoundError, msg):
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            graph.validate_consistency()
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    def test_remove_replaced_nodes(self):
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        """
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        Replaced nodes are properly removed and dependencies remapped.
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        """
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        # Add some dummy nodes to be replaced.
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        graph = MigrationGraph()
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        graph.add_dummy_node(key=("app_a", "0001"), origin="app_a.0002", error_message="BAD!")
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        graph.add_dummy_node(key=("app_a", "0002"), origin="app_b.0001", error_message="BAD!")
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        graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"), skip_validation=True)
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        # Add some normal parent and child nodes to test dependency remapping.
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        graph.add_node(("app_c", "0001"), None)
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        graph.add_node(("app_b", "0001"), None)
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        graph.add_dependency("app_a.0001", ("app_a", "0001"), ("app_c", "0001"), skip_validation=True)
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        graph.add_dependency("app_b.0001", ("app_b", "0001"), ("app_a", "0002"), skip_validation=True)
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        # Try replacing before replacement node exists.
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        msg = (
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            "Unable to find replacement node ('app_a', '0001_squashed_0002'). It was either"
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            " never added to the migration graph, or has been removed."
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        )
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        with self.assertRaisesMessage(NodeNotFoundError, msg):
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            graph.remove_replaced_nodes(
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                replacement=("app_a", "0001_squashed_0002"),
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                replaced=[("app_a", "0001"), ("app_a", "0002")]
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            )
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        graph.add_node(("app_a", "0001_squashed_0002"), None)
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        # Ensure `validate_consistency()` still raises an error at this stage.
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        with self.assertRaisesMessage(NodeNotFoundError, "BAD!"):
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            graph.validate_consistency()
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        # Remove the dummy nodes.
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        graph.remove_replaced_nodes(
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            replacement=("app_a", "0001_squashed_0002"),
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            replaced=[("app_a", "0001"), ("app_a", "0002")]
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        )
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        # Ensure graph is now consistent and dependencies have been remapped
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        graph.validate_consistency()
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        parent_node = graph.node_map[("app_c", "0001")]
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        replacement_node = graph.node_map[("app_a", "0001_squashed_0002")]
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        child_node = graph.node_map[("app_b", "0001")]
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        self.assertIn(parent_node, replacement_node.parents)
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        self.assertIn(replacement_node, parent_node.children)
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        self.assertIn(child_node, replacement_node.children)
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        self.assertIn(replacement_node, child_node.parents)
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    def test_remove_replacement_node(self):
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        """
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        A replacement node is properly removed and child dependencies remapped.
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        We assume parent dependencies are already correct.
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        """
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        # Add some dummy nodes to be replaced.
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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_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"))
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        # Try removing replacement node before replacement node exists.
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        msg = (
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            "Unable to remove replacement node ('app_a', '0001_squashed_0002'). It was"
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            " either never added to the migration graph, or has been removed already."
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        )
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        with self.assertRaisesMessage(NodeNotFoundError, msg):
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            graph.remove_replacement_node(
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                replacement=("app_a", "0001_squashed_0002"),
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                replaced=[("app_a", "0001"), ("app_a", "0002")]
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            )
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        graph.add_node(("app_a", "0001_squashed_0002"), None)
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        # Add a child node to test dependency remapping.
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        graph.add_node(("app_b", "0001"), None)
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        graph.add_dependency("app_b.0001", ("app_b", "0001"), ("app_a", "0001_squashed_0002"))
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        # Remove the replacement node.
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        graph.remove_replacement_node(
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            replacement=("app_a", "0001_squashed_0002"),
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            replaced=[("app_a", "0001"), ("app_a", "0002")]
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        )
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        # Ensure graph is consistent and child dependency has been remapped
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        graph.validate_consistency()
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        replaced_node = graph.node_map[("app_a", "0002")]
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        child_node = graph.node_map[("app_b", "0001")]
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        self.assertIn(child_node, replaced_node.children)
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        self.assertIn(replaced_node, child_node.parents)
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						|
        # 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), "<MigrationGraph: nodes=5, edges=3>")
 | 
						|
 | 
						|
 | 
						|
class NodeTests(SimpleTestCase):
 | 
						|
    def test_node_repr(self):
 | 
						|
        node = Node(('app_a', '0001'))
 | 
						|
        self.assertEqual(repr(node), "<Node: ('app_a', '0001')>")
 | 
						|
 | 
						|
    def test_dummynode_repr(self):
 | 
						|
        node = DummyNode(
 | 
						|
            key=('app_a', '0001'),
 | 
						|
            origin='app_a.0001',
 | 
						|
            error_message='x is missing',
 | 
						|
        )
 | 
						|
        self.assertEqual(repr(node), "<DummyNode: ('app_a', '0001')>")
 |