add test for succint role test case

tuf_conformance/test_updater_delegation_graphs.py

@@ -0,0 +1,127 @@
+from dataclasses import dataclass, field
+from typing import Any
+
+import pytest
+from tuf.api.metadata import (
+    TOP_LEVEL_ROLE_NAMES,
+)
+
+from tuf_conformance.client_runner import ClientRunner
+from tuf_conformance.simulator_server import SimulatorServer
+
+# DataSet is only here so type hints can be used.
+DataSet = dict[str, Any]
+
+
+@dataclass
+class DelegationTester:
+    delegator: str
+    rolename: str
+    keyids: list[str] = field(default_factory=list)
+    threshold: int = 1
+    terminating: bool = False
+    paths: list[str] | None = field(default_factory=lambda: ["*"])
+    path_hash_prefixes: list[str] | None = field(default_factory=list)
+
+
+@dataclass
+class TestTarget:
+    rolename: str
+    content: bytes
+    targetpath: str
+
+
+@dataclass
+class SuccinctRolesTestCase:
+    bit_length: int
+    target_path: str
+    expected_target_bin: str
+
+
+@dataclass
+class DelegationsTestCase:
+    """A delegations graph as lists of delegations and target files
+    and the expected order of traversal as a list of role names."""
+
+    delegations: list[DelegationTester]
+    target_files: list[TestTarget] = field(default_factory=list)
+    visited_order: list[str] = field(default_factory=list)
+
+
+succinct_bins_graph: DataSet = {
+    "bin amount = 2, taget bin index 0": SuccinctRolesTestCase(
+        bit_length=1,
+        target_path="boo",
+        expected_target_bin="bin-0",
+    ),
+    "bin amount = 2, taget bin index 1": SuccinctRolesTestCase(
+        bit_length=1,
+        target_path="too",
+        expected_target_bin="bin-1",
+    ),
+    "bin amount = 4, taget bin index 0": SuccinctRolesTestCase(
+        bit_length=2,
+        target_path="foo",
+        expected_target_bin="bin-0",
+    ),
+    "bin amount = 4, taget bin index 1": SuccinctRolesTestCase(
+        bit_length=2,
+        target_path="doo",
+        expected_target_bin="bin-1",
+    ),
+    "bin amount = 4, taget bin index 2": SuccinctRolesTestCase(
+        bit_length=2,
+        target_path="too",
+        expected_target_bin="bin-2",
+    ),
+    "bin amount = 4, taget bin index 3": SuccinctRolesTestCase(
+        bit_length=2,
+        target_path="bar",
+        expected_target_bin="bin-3",
+    ),
+    "bin amount = 256, taget bin index fc": SuccinctRolesTestCase(
+        bit_length=8,
+        target_path="bar",
+        expected_target_bin="bin-fc",
+    ),
+}
+
+
+succinct_bins_graph_ids = succinct_bins_graph.keys()
+succinct_bins_graph_cases = succinct_bins_graph.values()
+
+
+@pytest.mark.parametrize(
+    "succinct_bins_graph", succinct_bins_graph_cases, ids=succinct_bins_graph_ids
+)
+def test_succinct_roles_graph_traversal(
+    client: ClientRunner,
+    server: SimulatorServer,
+    succinct_bins_graph: SuccinctRolesTestCase,
+) -> None:
+    """Test traversing the delegation tree when succinct roles is used. For a
+    successful traversal all top level metadata files plus the expected
+    bin should exist locally and only one bin must be downloaded."""
+    exp_files = [*TOP_LEVEL_ROLE_NAMES, succinct_bins_graph.expected_target_bin]
+    exp_calls = [(succinct_bins_graph.expected_target_bin, 1)]
+
+    init_data, repo = server.new_test(client.test_name)
+    repo.add_succinct_roles("targets", succinct_bins_graph.bit_length, "bin")
+    repo.update_snapshot()
+    assert client.init_client(init_data) == 0
+    # Call explicitly refresh to simplify the expected_calls list.
+    assert client.refresh(init_data) == 0
+    repo.metadata_statistics.clear()
+    # Check that metadata dir contains only top-level roles
+    assert client._files_exist(TOP_LEVEL_ROLE_NAMES)
+
+    # Looking for a non-existing targetpath forces updater
+    # to visit a corresponding delegated role.
+    client.download_target(init_data, succinct_bins_graph.target_path)
+    # Here we could check that target_info is null. TODO: Add when
+    # support for storing the target_info is added.
+
+    # Check that the delegated roles were visited in the expected
+    # order and the corresponding metadata files were persisted.
+    assert repo.metadata_statistics[2:] == exp_calls
+    assert client._files_exist(exp_files)