Class TestIncrementalAstCache

tests/unit/ast_cache_test.py:212–640

class TestIncrementalAstCache(unittest.TestCase):
    def setUp(self):
        self._tmpdir = tempfile.TemporaryDirectory()
        self.tmp = Path(self._tmpdir.name)

    def tearDown(self):
        self._tmpdir.cleanup()

    def _write(self, name: str, content: str) -> Path:
        p = self.tmp / name
        p.write_text(content, encoding="utf-8")
        return p

    def _l1_key(self, p: Path) -> str:
        """Return the L1 dict key for a path (always the resolved form)."""
        return str(p.resolve())

    # ── L1 mtime hit ──────────────────────────────────────────────────────

    def test_l1_mtime_hit_skips_hash(self):
        cache = _make_cache(self.tmp)
        src = "def foo(): pass\n"
        p = self._write("a.py", src)

        cache.get_ast_json(p, src)  # populate L1

        with patch("pyspector.ast_cache.hashlib") as mock_hash:
            cache.get_ast_json(p, src)  # same mtime → must not hash
            mock_hash.sha256.assert_not_called()

    # ── L1 hash hit ───────────────────────────────────────────────────────

    def test_l1_hash_hit_updates_mtime(self):
        cache = _make_cache(self.tmp)
        src = "x = 1\n"
        p = self._write("b.py", src)

        cache.get_ast_json(p, src)
        entry_before = cache._l1[self._l1_key(p)]
        old_mtime = entry_before.mtime

        # Touch the file (change mtime without changing content)
        os.utime(p, (old_mtime + 1, old_mtime + 1))
        cache.get_ast_json(p, src)

        entry_after = cache._l1[self._l1_key(p)]
        self.assertNotEqual(entry_after.mtime, old_mtime)
        # Same bytes object (shallow copy via dataclasses.replace — no rebuild)
        self.assertIs(entry_before.full_ast_json_z, entry_after.full_ast_json_z)

    # ── L2 disk hit ───────────────────────────────────────────────────────

    def test_l2_disk_survives_l1_eviction(self):
        cache = _make_cache(self.tmp)
        src = "def saved(): pass\n"
        p = self._write("c.py", src)

        cache.get_ast_json(p, src)  # write to disk