def test_validate_consistency(self):
"""
Tests for missing nodes, using `validate_consistency()` to raise the error.
"""
# Build graph
graph = MigrationGraph()
graph.add_node(("app_a", "0001"), None)
# Add dependency with missing parent node (skipping validation).
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()
# Add missing parent node and ensure `validate_consistency()` no longer raises error.
graph.add_node(("app_b", "0002"), None)
graph.validate_consistency()
# Add dependency with missing child node (skipping validation).
graph.add_dependency("app_a.0002", ("app_a", "0002"), ("app_a", "0001"), skip_validation=True)
msg = "Migration app_a.0002 dependencies reference nonexistent child node ('app_a', '0002')"
with self.assertRaisesMessage(NodeNotFoundError, msg):
graph.validate_consistency()
# Add missing child node and ensure `validate_consistency()` no longer raises error.
graph.add_node(("app_a", "0002"), None)
graph.validate_consistency()
# Rawly add dummy node.
msg = "app_a.0001 (req'd by app_a.0002) is missing!"
graph.add_dummy_node(
key=("app_a", "0001"),
origin="app_a.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)