diff --git a/model-engine/tests/test_database_migration_adoption.py b/model-engine/tests/test_database_migration_adoption.py
new file mode 100644
index 00000000..04c0a5a2
--- /dev/null
+++ b/model-engine/tests/test_database_migration_adoption.py
@@ -0,0 +1,169 @@
+from importlib.util import module_from_spec, spec_from_file_location
+from pathlib import Path
+from typing import Any
+from unittest.mock import Mock, mock_open, patch
+
+import pytest
+
+VERSIONS_DIR = (
+    Path(__file__).parents[1] / "model_engine_server" / "db" / "migrations" / "alembic" / "versions"
+)
+
+INITIAL_MIGRATION = "2024_09_09_1736-fa3267c80731_initial.py"
+
+ADD_COLUMN_MIGRATIONS = [
+    (
+        "2024_09_09_1831-b574e9711e35_chat_completion_add_extra_routes.py",
+        [("bundles", "runnable_image_extra_routes")],
+    ),
+    (
+        "2024_09_24_1456-f55525c81eb5_multinode_bundle.py",
+        [
+            ("bundles", "runnable_image_worker_command"),
+            ("bundles", "runnable_image_worker_env"),
+        ],
+    ),
+    (
+        "2025_09_16_1741-e580182d6bfd_add_passthrough_forwarder.py",
+        [("bundles", "runnable_image_forwarder_type")],
+    ),
+    (
+        "2025_09_25_1940-221aa19d3f32_add_routes_column.py",
+        [("bundles", "runnable_image_routes")],
+    ),
+    (
+        "2026_02_10_1920-62da4f8b3403_add_task_expires_seconds_column.py",
+        [("endpoints", "task_expires_seconds")],
+    ),
+    (
+        "2026_02_20_1200-a1b2c3d4e5f6_add_queue_message_timeout_seconds_column.py",
+        [("endpoints", "queue_message_timeout_seconds")],
+    ),
+    (
+        "2026_06_16_1200-c4d5e6f7a8b9_add_status_reason_column.py",
+        [("endpoints", "status_reason")],
+    ),
+]
+
+
+def load_migration(filename: str) -> Any:
+    path = VERSIONS_DIR / filename
+    spec = spec_from_file_location(path.stem.replace("-", "_"), path)
+    assert spec is not None
+    assert spec.loader is not None
+    module = module_from_spec(spec)
+    spec.loader.exec_module(module)
+    return module
+
+
+def test_initial_migration_adopts_an_existing_schema(monkeypatch: pytest.MonkeyPatch) -> None:
+    migration = load_migration(INITIAL_MIGRATION)
+    inspector = Mock()
+    inspector.has_table.return_value = True
+    operation = Mock()
+    monkeypatch.setattr(migration.sa, "inspect", Mock(return_value=inspector))
+    monkeypatch.setattr(migration, "op", operation)
+
+    with patch("builtins.open", mock_open()) as open_file:
+        migration.upgrade()
+
+    inspector.has_table.assert_called_once_with("endpoints", schema="hosted_model_inference")
+    open_file.assert_not_called()
+    operation.execute.assert_not_called()
+
+
+def test_initial_migration_initializes_an_empty_database(monkeypatch: pytest.MonkeyPatch) -> None:
+    migration = load_migration(INITIAL_MIGRATION)
+    inspector = Mock()
+    inspector.has_table.return_value = False
+    operation = Mock()
+    monkeypatch.setattr(migration.sa, "inspect", Mock(return_value=inspector))
+    monkeypatch.setattr(migration, "op", operation)
+
+    with patch("builtins.open", mock_open(read_data="SELECT 1;")) as open_file:
+        migration.upgrade()
+
+    open_file.assert_called_once_with(migration.INITIAL_MIGRATION_PATH)
+    operation.execute.assert_called_once_with("SELECT 1;")
+
+
+@pytest.mark.parametrize(("filename", "columns"), ADD_COLUMN_MIGRATIONS)
+def test_upgrade_skips_columns_that_already_exist(
+    filename: str,
+    columns: list[tuple[str, str]],
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    migration = load_migration(filename)
+    inspector = Mock()
+    inspector.get_columns.return_value = [{"name": column} for _, column in columns]
+    operation = Mock()
+    monkeypatch.setattr(migration.sa, "inspect", Mock(return_value=inspector))
+    monkeypatch.setattr(migration, "op", operation)
+
+    migration.upgrade()
+
+    operation.add_column.assert_not_called()
+
+
+@pytest.mark.parametrize(("filename", "columns"), ADD_COLUMN_MIGRATIONS)
+def test_upgrade_adds_only_missing_columns(
+    filename: str,
+    columns: list[tuple[str, str]],
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    migration = load_migration(filename)
+    inspector = Mock()
+    inspector.get_columns.return_value = []
+    operation = Mock()
+    monkeypatch.setattr(migration.sa, "inspect", Mock(return_value=inspector))
+    monkeypatch.setattr(migration, "op", operation)
+
+    migration.upgrade()
+
+    added_columns = [
+        (call.args[0], call.args[1].name, call.kwargs["schema"])
+        for call in operation.add_column.call_args_list
+    ]
+    assert added_columns == [(table, column, "hosted_model_inference") for table, column in columns]
+
+
+@pytest.mark.parametrize(("filename", "columns"), ADD_COLUMN_MIGRATIONS)
+def test_downgrade_skips_columns_that_are_already_absent(
+    filename: str,
+    columns: list[tuple[str, str]],
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    migration = load_migration(filename)
+    inspector = Mock()
+    inspector.get_columns.return_value = []
+    operation = Mock()
+    monkeypatch.setattr(migration.sa, "inspect", Mock(return_value=inspector))
+    monkeypatch.setattr(migration, "op", operation)
+
+    migration.downgrade()
+
+    operation.drop_column.assert_not_called()
+
+
+@pytest.mark.parametrize(("filename", "columns"), ADD_COLUMN_MIGRATIONS)
+def test_downgrade_drops_only_existing_columns(
+    filename: str,
+    columns: list[tuple[str, str]],
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    migration = load_migration(filename)
+    inspector = Mock()
+    inspector.get_columns.return_value = [{"name": column} for _, column in columns]
+    operation = Mock()
+    monkeypatch.setattr(migration.sa, "inspect", Mock(return_value=inspector))
+    monkeypatch.setattr(migration, "op", operation)
+
+    migration.downgrade()
+
+    dropped_columns = [
+        (call.args[0], call.args[1], call.kwargs["schema"])
+        for call in operation.drop_column.call_args_list
+    ]
+    assert dropped_columns == [
+        (table, column, "hosted_model_inference") for table, column in columns
+    ]