merge: testing → main (reconcile 2-week divergence)

tests/service_testing/test_instance_seed.py

@@ -0,0 +1,91 @@
+"""
+Tests for decnet/templates/instance_seed.py — the per-instance stealth
+seeding helper. These tests pin NODE_NAME to assert determinism of the
+seeded functions, and sweep NODE_NAMEs to assert cross-fleet divergence.
+"""
+
+import asyncio
+import importlib.util
+import sys
+import time
+from unittest.mock import patch
+
+
+def _load_seed(node_name: str):
+    sys.modules.pop("instance_seed", None)
+    spec = importlib.util.spec_from_file_location(
+        "instance_seed", "decnet/templates/instance_seed.py"
+    )
+    mod = importlib.util.module_from_spec(spec)
+    with patch.dict("os.environ", {"NODE_NAME": node_name}, clear=False):
+        spec.loader.exec_module(mod)
+    return mod
+
+
+def test_same_nodename_yields_stable_uuid():
+    a = _load_seed("deckie-42").instance_uuid("x")
+    b = _load_seed("deckie-42").instance_uuid("x")
+    assert a == b
+
+
+def test_different_nodename_yields_different_uuid():
+    a = _load_seed("deckie-alpha").instance_uuid("x")
+    b = _load_seed("deckie-beta").instance_uuid("x")
+    assert a != b
+
+
+def test_pick_is_deterministic_per_instance():
+    choices = ["a", "b", "c", "d", "e"]
+    m1 = _load_seed("hostX")
+    m2 = _load_seed("hostX")
+    assert m1.pick(choices) == m2.pick(choices)
+
+
+def test_pick_varies_across_fleet():
+    """For a reasonable fleet size, pick should land on at least 2 distinct
+    values. Anything less means the seed isn't actually diversifying output."""
+    choices = list("abcdefghij")
+    picks = {_load_seed(f"host{i}").pick(choices) for i in range(20)}
+    assert len(picks) >= 3
+
+
+def test_uptime_monotonic_across_calls():
+    mod = _load_seed("uptime-host")
+    u1 = mod.uptime_seconds()
+    time.sleep(0.02)
+    u2 = mod.uptime_seconds()
+    assert u2 >= u1
+
+
+def test_uptime_includes_boot_offset():
+    """uptime should be > a few minutes even at process start — deckies
+    should not look like they just booted."""
+    mod = _load_seed("fresh-host")
+    assert mod.uptime_seconds() > 600
+
+
+def test_fresh_bytes_is_not_deterministic():
+    """fresh_bytes is per-connection randomness, not seeded — otherwise
+    two MySQL handshakes to the same decky would present identical salts."""
+    mod = _load_seed("host")
+    assert mod.fresh_bytes(16) != mod.fresh_bytes(16)
+
+
+def test_random_bytes_is_deterministic():
+    """random_bytes is the *seeded* variant — used for stable per-instance
+    identifiers like cluster UUIDs."""
+    a = _load_seed("h").random_bytes(16, "ns")
+    b = _load_seed("h").random_bytes(16, "ns")
+    assert a == b
+
+
+def test_jitter_sleeps_in_range():
+    mod = _load_seed("jh")
+
+    async def run():
+        start = time.perf_counter()
+        await mod.jitter(10, 30)
+        return time.perf_counter() - start
+
+    elapsed = asyncio.run(run())
+    assert 0.005 <= elapsed <= 0.200  # generous upper bound for CI jitter