|
| 1 | +"""Focused unit tests for the state-migration surface. |
| 2 | +
|
| 3 | +The conformance suite (``tests/conformance/test_state_migration.py``) |
| 4 | +covers the spec's behavioral surface end-to-end against fixtures |
| 5 | +039-046. These unit tests fill gaps the fixtures don't exercise |
| 6 | +directly: BFS edge cases on the registry, multi-shortest-path |
| 7 | +ambiguity detection, GraphBuilder ergonomics, and the error |
| 8 | +attribute carriage shape. |
| 9 | +""" |
| 10 | + |
| 11 | +from __future__ import annotations |
| 12 | + |
| 13 | +import pytest |
| 14 | + |
| 15 | +from openarmature.checkpoint import ( |
| 16 | + CheckpointStateMigrationFailed, |
| 17 | + CheckpointStateMigrationMissing, |
| 18 | + MigrationRegistry, |
| 19 | + StateMigration, |
| 20 | +) |
| 21 | +from openarmature.graph import END, GraphBuilder, State |
| 22 | + |
| 23 | +# --------------------------------------------------------------------------- |
| 24 | +# MigrationRegistry — basic registration + iteration + describe |
| 25 | +# --------------------------------------------------------------------------- |
| 26 | + |
| 27 | + |
| 28 | +def _id(x: int) -> int: |
| 29 | + return x |
| 30 | + |
| 31 | + |
| 32 | +def test_registry_empty_describes_with_sentinel() -> None: |
| 33 | + registry = MigrationRegistry() |
| 34 | + assert len(registry) == 0 |
| 35 | + assert registry.describe() == "<no migrations registered>" |
| 36 | + |
| 37 | + |
| 38 | +def test_registry_lists_registered_in_order() -> None: |
| 39 | + registry = MigrationRegistry() |
| 40 | + registry.register(StateMigration(from_version="v1", to_version="v2", migrate=_id)) |
| 41 | + registry.register(StateMigration(from_version="v2", to_version="v3", migrate=_id)) |
| 42 | + assert len(registry) == 2 |
| 43 | + assert "v1 → v2" in registry.describe() |
| 44 | + assert "v2 → v3" in registry.describe() |
| 45 | + |
| 46 | + |
| 47 | +def test_registry_rejects_duplicate_edge() -> None: |
| 48 | + registry = MigrationRegistry() |
| 49 | + registry.register(StateMigration(from_version="v1", to_version="v2", migrate=_id)) |
| 50 | + with pytest.raises(ValueError, match="duplicate state migration"): |
| 51 | + registry.register(StateMigration(from_version="v1", to_version="v2", migrate=_id)) |
| 52 | + |
| 53 | + |
| 54 | +# --------------------------------------------------------------------------- |
| 55 | +# Chain resolution — empty, identity, single hop, multi hop |
| 56 | +# --------------------------------------------------------------------------- |
| 57 | + |
| 58 | + |
| 59 | +def test_resolve_chain_same_version_returns_empty_chain() -> None: |
| 60 | + registry = MigrationRegistry() |
| 61 | + chain = registry.resolve_chain("v1", "v1") |
| 62 | + assert chain == [] |
| 63 | + |
| 64 | + |
| 65 | +def test_resolve_chain_empty_registry_returns_none() -> None: |
| 66 | + registry = MigrationRegistry() |
| 67 | + assert registry.resolve_chain("v1", "v2") is None |
| 68 | + |
| 69 | + |
| 70 | +def test_resolve_chain_unrelated_registry_returns_none() -> None: |
| 71 | + registry = MigrationRegistry() |
| 72 | + registry.register(StateMigration(from_version="v3", to_version="v4", migrate=_id)) |
| 73 | + assert registry.resolve_chain("v1", "v2") is None |
| 74 | + |
| 75 | + |
| 76 | +def test_resolve_chain_single_hop() -> None: |
| 77 | + registry = MigrationRegistry() |
| 78 | + a_to_b = StateMigration(from_version="a", to_version="b", migrate=_id) |
| 79 | + registry.register(a_to_b) |
| 80 | + chain = registry.resolve_chain("a", "b") |
| 81 | + assert chain == [a_to_b] |
| 82 | + |
| 83 | + |
| 84 | +def test_resolve_chain_multi_hop_in_order() -> None: |
| 85 | + registry = MigrationRegistry() |
| 86 | + a_to_b = StateMigration(from_version="a", to_version="b", migrate=_id) |
| 87 | + b_to_c = StateMigration(from_version="b", to_version="c", migrate=_id) |
| 88 | + c_to_d = StateMigration(from_version="c", to_version="d", migrate=_id) |
| 89 | + # Register out of natural order to verify BFS doesn't depend on |
| 90 | + # registration order. |
| 91 | + registry.register(c_to_d) |
| 92 | + registry.register(a_to_b) |
| 93 | + registry.register(b_to_c) |
| 94 | + chain = registry.resolve_chain("a", "d") |
| 95 | + assert chain == [a_to_b, b_to_c, c_to_d] |
| 96 | + |
| 97 | + |
| 98 | +def test_resolve_chain_picks_shortest_when_unique() -> None: |
| 99 | + """A short path exists alongside a longer one; BFS picks the short.""" |
| 100 | + registry = MigrationRegistry() |
| 101 | + # Diamond with an extra step on one side. |
| 102 | + registry.register(StateMigration(from_version="v1", to_version="v2", migrate=_id)) |
| 103 | + registry.register(StateMigration(from_version="v2", to_version="v3", migrate=_id)) |
| 104 | + # Long detour: v1 -> v1a -> v1b -> v3. |
| 105 | + registry.register(StateMigration(from_version="v1", to_version="v1a", migrate=_id)) |
| 106 | + registry.register(StateMigration(from_version="v1a", to_version="v1b", migrate=_id)) |
| 107 | + registry.register(StateMigration(from_version="v1b", to_version="v3", migrate=_id)) |
| 108 | + chain = registry.resolve_chain("v1", "v3") |
| 109 | + assert chain is not None |
| 110 | + assert [(m.from_version, m.to_version) for m in chain] == [ |
| 111 | + ("v1", "v2"), |
| 112 | + ("v2", "v3"), |
| 113 | + ] |
| 114 | + |
| 115 | + |
| 116 | +def test_resolve_chain_ambiguous_shortest_paths_raises() -> None: |
| 117 | + """Diamond with two distinct same-length paths is ambiguous per spec §10.12.2.""" |
| 118 | + registry = MigrationRegistry() |
| 119 | + registry.register(StateMigration(from_version="v1", to_version="v2", migrate=_id)) |
| 120 | + registry.register(StateMigration(from_version="v1", to_version="v3", migrate=_id)) |
| 121 | + registry.register(StateMigration(from_version="v2", to_version="v4", migrate=_id)) |
| 122 | + registry.register(StateMigration(from_version="v3", to_version="v4", migrate=_id)) |
| 123 | + with pytest.raises(ValueError, match="ambiguous migration chain"): |
| 124 | + registry.resolve_chain("v1", "v4") |
| 125 | + |
| 126 | + |
| 127 | +# --------------------------------------------------------------------------- |
| 128 | +# GraphBuilder ergonomics — singular + plural registration |
| 129 | +# --------------------------------------------------------------------------- |
| 130 | + |
| 131 | + |
| 132 | +class _Sv1(State): |
| 133 | + schema_version = "v1" |
| 134 | + x: int = 0 |
| 135 | + |
| 136 | + |
| 137 | +def _build_minimal_graph() -> GraphBuilder[_Sv1]: |
| 138 | + async def _noop(_s: _Sv1) -> dict[str, int]: |
| 139 | + return {} |
| 140 | + |
| 141 | + return GraphBuilder(_Sv1).add_node("noop", _noop).add_edge("noop", END).set_entry("noop") |
| 142 | + |
| 143 | + |
| 144 | +def test_builder_with_state_migration_singular() -> None: |
| 145 | + builder = _build_minimal_graph() |
| 146 | + builder.with_state_migration("v0", "v1", _id) |
| 147 | + compiled = builder.compile() |
| 148 | + assert len(compiled.migration_registry) == 1 |
| 149 | + |
| 150 | + |
| 151 | +def test_builder_with_state_migrations_plural() -> None: |
| 152 | + builder = _build_minimal_graph() |
| 153 | + builder.with_state_migrations( |
| 154 | + StateMigration(from_version="v0", to_version="v1", migrate=_id), |
| 155 | + StateMigration(from_version="v1", to_version="v2", migrate=_id), |
| 156 | + ) |
| 157 | + compiled = builder.compile() |
| 158 | + assert len(compiled.migration_registry) == 2 |
| 159 | + |
| 160 | + |
| 161 | +def test_builder_duplicate_registration_raises() -> None: |
| 162 | + builder = _build_minimal_graph() |
| 163 | + builder.with_state_migration("v0", "v1", _id) |
| 164 | + with pytest.raises(ValueError, match="duplicate state migration"): |
| 165 | + builder.with_state_migration("v0", "v1", _id) |
| 166 | + |
| 167 | + |
| 168 | +# --------------------------------------------------------------------------- |
| 169 | +# Error attribute carriage |
| 170 | +# --------------------------------------------------------------------------- |
| 171 | + |
| 172 | + |
| 173 | +def test_migration_missing_carries_identity() -> None: |
| 174 | + exc = CheckpointStateMigrationMissing( |
| 175 | + "no chain", |
| 176 | + from_version="v1", |
| 177 | + to_version="v2", |
| 178 | + registered_migrations_count=3, |
| 179 | + registry_description="v3 → v4\nv5 → v6\nv7 → v8", |
| 180 | + ) |
| 181 | + assert exc.from_version == "v1" |
| 182 | + assert exc.to_version == "v2" |
| 183 | + assert exc.registered_migrations_count == 3 |
| 184 | + assert "v3 → v4" in exc.registry_description |
| 185 | + |
| 186 | + |
| 187 | +def test_migration_failed_carries_identity() -> None: |
| 188 | + exc = CheckpointStateMigrationFailed( |
| 189 | + "boom", |
| 190 | + from_version="v1", |
| 191 | + to_version="v2", |
| 192 | + ) |
| 193 | + assert exc.from_version == "v1" |
| 194 | + assert exc.to_version == "v2" |
| 195 | + |
| 196 | + |
| 197 | +def test_migration_failed_preserves_cause_when_raised_from() -> None: |
| 198 | + """The error's ``__cause__`` carries the original migration |
| 199 | + exception when raised from a try/except. This mirrors the engine's |
| 200 | + chain-application wrap.""" |
| 201 | + underlying = KeyError("missing field") |
| 202 | + try: |
| 203 | + try: |
| 204 | + raise underlying |
| 205 | + except KeyError as exc: |
| 206 | + raise CheckpointStateMigrationFailed( |
| 207 | + "boom", |
| 208 | + from_version="v1", |
| 209 | + to_version="v2", |
| 210 | + ) from exc |
| 211 | + except CheckpointStateMigrationFailed as final: |
| 212 | + assert final.__cause__ is underlying |
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