import errno
import importlib.util
import os
from pathlib import Path
import tempfile
import unittest
from unittest import mock

SPEC=importlib.util.spec_from_file_location('pagefs',Path(__file__).resolve().parents[1]/'pagefs.py')
m=importlib.util.module_from_spec(SPEC);SPEC.loader.exec_module(m)

class EngineTests(unittest.TestCase):
    def setUp(self):
        self.tmp=tempfile.TemporaryDirectory();self.path=Path(self.tmp.name)/'image'
    def tearDown(self):self.tmp.cleanup()
    def create(self,files=None,pool=512):return m.PageStore.create(self.path,initial_files=files,pool_blocks=pool)
    def damage(self,offset,n):
        with open(self.path,'r+b',buffering=0) as f:f.seek(offset);f.write(bytes(n));os.fsync(f.fileno())
    def test_genesis_and_fixed_capacity(self):
        with self.create({'/a':b'x'}) as s:
            self.assertEqual(s.get('/a'),b'x');self.assertEqual(s.epoch,0)
            self.assertEqual(os.stat(self.path).st_size,m.POOL_START+512*m.BLOCK_SIZE)
            self.assertEqual(len(s._live_blocks)+len(s._free),s.pool_blocks)
    def test_transaction_one_force_two_writes(self):
        with self.create() as s:
            s.reset_stats();self.assertEqual(s.transact({'/a':b'x','/b':b'y'},'tx'),1)
            self.assertEqual(s.stats['write_calls'],2);self.assertEqual(s.stats['fsync_calls'],1)
            self.assertEqual(s.stats['page_allocations'],0)
    def test_multi_path_delete_and_reopen(self):
        with self.create({'/a':b'old','/b':b'b'}) as s:
            s.transact({'/a':b'new','/b':None,'/missing':None},'one')
        with m.PageStore(self.path,writable=False) as s:
            self.assertEqual(s.files(),['/a']);self.assertEqual(s.get('/a'),b'new');self.assertEqual(s.query('one')['epoch'],1)
    def test_retry_is_no_io_and_survives_checkpoint(self):
        with self.create() as s:
            s.transact({'/a':b'x'},'same');s.checkpoint();s.reset_stats()
            self.assertEqual(s.transact({'/a':b'x'},'same'),1);self.assertEqual(s.stats['write_calls'],0)
            with self.assertRaises(m.TransactionConflict):s.transact({'/a':b'y'},'same')
        with m.PageStore(self.path) as s:self.assertEqual(s.transact({'/a':b'x'},'same'),1)
    def test_unicode_escaped_keys(self):
        data={'/雪/"name\n':b'\x00\xff','/emoji😀':b''}
        with self.create(data) as s:s.checkpoint()
        with m.PageStore(self.path,writable=False) as s:
            for key,value in data.items():self.assertEqual(s.get(key),value)
    def test_invalid_creation_inputs_have_no_file(self):
        for files in ({'/a':bytes(m.MAX_CAPSULE+1)},{'relative':b'a'},{'/a':'str'}):
            with self.assertRaises((ValueError,TypeError)):self.create(files)
            self.assertFalse(self.path.exists())
    def test_overescaped_path_rejected_before_ack(self):
        with self.create() as s:
            s.reset_stats()
            with self.assertRaises(ValueError):s.transact({'/'+chr(1)*1000:b'x'},'bad')
            self.assertEqual(s.stats['write_calls'],0)
    def test_volatile_caches_match_exact_live_identities(self):
        with self.create(pool=256) as s:
            for i in range(60):
                s.transact({'/a':str(i).encode()},f't{i}');s.checkpoint()
                self.assertEqual(set(s._cache),set(s._refs))
                self.assertEqual(set(s._graph_cache),set(s._refs))
    def test_initial_largest_value(self):
        raw=bytes(range(256))*(m.MAX_CAPSULE//256)+bytes(m.MAX_CAPSULE%256)
        with self.create({'/large':raw}):pass
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/large'),raw)
    def test_capsule_size_rejected_without_io(self):
        with self.create() as s:
            s.reset_stats()
            with self.assertRaises(ValueError):s.transact({'/a':bytes(m.MAX_CAPSULE)},'large')
            self.assertEqual(s.stats['write_calls'],0);self.assertFalse(s.fenced)
    def test_inline_boundary_and_blob(self):
        for size in (0,1,255,256,257,m.PAGE_PAYLOAD,m.PAGE_PAYLOAD+1,30000):
            with self.subTest(size=size):
                with self.create() as s:
                    value=bytes([size%256])*size;s.transact({'/a':value},'one');s.checkpoint()
                with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/a'),value)
                self.path.unlink()
    def test_tree_splits_and_delete_preserve_neighbors(self):
        files={f'/f{i}':bytes([i%256])*128 for i in range(300)}
        with self.create(files,pool=1024) as s:
            s.transact({'/f155':None,'/f156':b'changed'},'one');s.checkpoint()
        files.pop('/f155');files['/f156']=b'changed'
        with m.PageStore(self.path,writable=False) as s:
            self.assertEqual(s.files(),sorted(files))
            for key,value in files.items():self.assertEqual(s.get(key),value)
    def test_unchanged_subtree_reused(self):
        with self.create({f'/f{i}':bytes(128) for i in range(300)},pool=1024) as s:
            old=m.unpack_json(s._read_object(s.files_root,m.K_TRIE))['children']
            s.transact({'/f1':b'new'},'one');s.checkpoint()
            new=m.unpack_json(s._read_object(s.files_root,m.K_TRIE))['children']
            nib=m.hash_key('/f1')[0]
            for key in old:
                if key!=nib:self.assertEqual(old[key],new[key])
    def test_cold_blobs_not_redecoded_during_checkpoint(self):
        with self.create({f'/f{i}':bytes([i])*4000 for i in range(32)},pool=1024) as s:
            s.transact({'/new':b'x'},'one')
            original=m.unb64;calls=[]
            def counted(value):calls.append(len(value));return original(value)
            with mock.patch.object(m,'unb64',counted):s.checkpoint()
            self.assertLess(max(calls,default=0),100)
    def test_automatic_pressure_checkpoint(self):
        with self.create() as s:
            for i in range(65):s.transact({'/a':str(i).encode()},f't{i}')
            self.assertEqual(s.checkpoint_epoch,64);self.assertEqual(len(s.active),1)
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.epoch,65);self.assertEqual(s.get('/a'),b'64')
    def test_reuse_keeps_file_bounded(self):
        with self.create(pool=256) as s:
            size=os.stat(self.path).st_size
            for i in range(300):
                s.transact({'/a':bytes([i%256])*1000},f't{i}')
                if i%20==19:s.checkpoint()
            self.assertGreater(s.stats['reclaimed_blocks'],256)
            self.assertEqual(os.stat(self.path).st_size,size)
            self.assertFalse(set(s._free)&s._live_blocks)
            self.assertEqual(len(set(s._free))+len(s._live_blocks),256)
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/a'),bytes([299%256])*1000)
    def test_empty_checkpoint_and_reopen(self):
        with self.create() as s:
            for _ in range(5):self.assertEqual(s.checkpoint(),0)
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.epoch,0)
    def test_read_only_cannot_mutate(self):
        with self.create():pass
        with m.PageStore(self.path,writable=False) as s:
            with self.assertRaises(m.WriterFenced):s.transact({'/a':b'a'},'x')
            with self.assertRaises(m.WriterFenced):s.checkpoint()
    def test_single_pool_mirror_recovery_and_repair(self):
        with self.create({'/a':b'x'}) as s:root=list(s.catalog_desc)
        self.damage(m.block_offset(root[0]),m.BLOCK_SIZE)
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/a'),b'x')
        with m.PageStore(self.path) as s:self.assertGreater(s.stats['write_calls'],0)
        self.damage(m.block_offset(root[1]),m.BLOCK_SIZE)
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/a'),b'x')
    def test_both_newest_root_mirrors_block_fallback(self):
        with self.create({'/a':b'old'}) as s:
            s.transact({'/a':b'new'},'one');s.checkpoint();root=list(s.catalog_desc)
        for index in root[:2]:self.damage(m.block_offset(index),m.BLOCK_SIZE)
        with self.assertRaises(m.RecoveryBlocked):m.PageStore(self.path,writable=False)
    def test_capsule_mirror_repair(self):
        with self.create() as s:s.transact({'/a':b'x'},'one')
        self.damage(m.capsule_offset(1,0),m.SPAN)
        with m.PageStore(self.path) as s:self.assertEqual(s.get('/a'),b'x');self.assertGreater(s.stats['write_calls'],0)
        self.damage(m.capsule_offset(1,1),m.SPAN)
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/a'),b'x')
    def test_valid_header_without_payload_blocks(self):
        with self.create() as s:s.transact({'/a':b'x'},'one')
        for replica in range(2):self.damage(m.capsule_offset(1,replica)+m.HEADER.size,400)
        with self.assertRaises(m.RecoveryBlocked):m.PageStore(self.path,writable=False)
    def test_single_latest_seal_is_normalized(self):
        with self.create() as s:s.transact({'/a':b'x'},'one');s.checkpoint();generation=s.generation
        pair=range((generation%2)*2,(generation%2)*2+2)
        self.damage(m.SEAL_OFFSETS[list(pair)[0]],m.SECTOR)
        with m.PageStore(self.path) as s:self.assertEqual(len(s._selected_valid_slots),2)
    def test_dependency_failure_fences_and_preserves_ack(self):
        with self.create({'/a':b'old'}) as s:
            s.transact({'/a':b'new'},'one')
            with mock.patch.object(s,'_sync',side_effect=OSError('force failed')):
                with self.assertRaises(OSError):s.checkpoint()
            self.assertTrue(s.fenced)
            with self.assertRaises(m.WriterFenced):s.get('/a')
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/a'),b'new');self.assertEqual(s.query('one')['epoch'],1)
    def test_publication_failure_fences_and_reopens(self):
        with self.create() as s:
            s.transact({'/a':b'x'},'one');original=s._pwrite
            def fail_seals(raw,off):
                if off in m.SEAL_OFFSETS:raise OSError('seal failed')
                original(raw,off)
            with mock.patch.object(s,'_pwrite',fail_seals):
                with self.assertRaises(OSError):s.checkpoint()
            self.assertTrue(s.fenced)
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/a'),b'x')
    def test_enospc_offer_rejected_before_ack(self):
        with self.create(pool=16) as s:
            s.reset_stats();before=self.path.read_bytes()
            with self.assertRaises(m.AdmissionRejected) as caught:s.transact({'/a':bytes(16000)},'not-ack')
            self.assertEqual(caught.exception.errno,errno.ENOSPC);self.assertFalse(s.fenced)
            self.assertEqual(s.epoch,0);self.assertIsNone(s.query('not-ack'))
            self.assertEqual(s.stats['write_calls'],0);self.assertEqual(before,self.path.read_bytes())
            s.transact({'/a':b'fits'},'ack');s.checkpoint()
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/a'),b'fits');self.assertIsNotNone(s.query('ack'))
    def test_transaction_adoption_exception_fences(self):
        with self.create() as s:
            with mock.patch.object(s,'_apply',side_effect=RuntimeError('RAM failure')):
                with self.assertRaises(RuntimeError):s.transact({'/a':b'x'},'one')
            self.assertTrue(s.fenced)
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/a'),b'x')
    def test_minimum_epoch(self):
        with self.create():pass
        with self.assertRaises(m.RecoveryBlocked):m.PageStore(self.path,writable=False,minimum_epoch=1)
    def test_exclusive_writer(self):
        with self.create():
            with self.assertRaises(BlockingIOError):m.PageStore(self.path)
    def test_descriptor_future_birth_rejected(self):
        with self.create({'/a':b'x'}) as s:
            root=list(s.catalog_desc);root[2]+=1
            with self.assertRaises(m.InvalidImage):s._scan_graph(root)
    def test_generation_exhaustion_no_io(self):
        with self.create() as s:
            s.generation=m.MAX_U64;s.reset_stats()
            with self.assertRaises(m.StoreError):s.checkpoint()
            self.assertEqual(s.stats['write_calls'],0)
    def test_checkpoint_avoids_full_scan_and_pool_rebuild(self):
        with self.create({f'/f{i}':bytes(128) for i in range(500)},pool=1024) as s:
            s.transact({'/f1':b'changed'},'one');s.reset_stats();s.checkpoint()
            self.assertEqual(s.stats['full_graph_scans'],0)
            self.assertEqual(s.stats['pool_rebuilds'],0)
            self.assertEqual(s.stats['incremental_validations'],1)
            self.assertLess(s.stats['graph_nodes_validated'],20)
            self.assertLess(s.stats['refcount_steps'],100)
    def test_incremental_refcounts_equal_independent_full_graph(self):
        with self.create({f'/f{i}':bytes(128) for i in range(100)},pool=512) as s:
            for i in range(80):
                s.transact({f'/f{i%100}':None if i%3==0 else str(i).encode()},f't{i}')
                if i%8==7:
                    s.checkpoint()
                    _,blocks,_,_=s._scan_graph(s.catalog_desc)
                    self.assertEqual(blocks,s._live_blocks)
                    self.assertEqual(set(s._refs),set(s._graph_cache))
                    self.assertTrue(all(count==1 for count in s._refs.values()))
                    self.assertEqual(set(s._free),set(range(s.pool_blocks))-blocks)
    def test_candidate_and_selected_roots_pinned_before_publication(self):
        with self.create({'/a':bytes(8000)},pool=256) as s:
            old=set(s._live_blocks);s.transact({'/a':b'new'},'one')
            original=s._sync;calls=[]
            def observe():
                calls.append(set(s._live_blocks));self.assertTrue(old<=s._live_blocks)
                return original()
            with mock.patch.object(s,'_sync',observe):s.checkpoint()
            self.assertEqual(len(calls),2);self.assertGreater(len(calls[0]),len(s._live_blocks))
    def test_unreachable_reserved_allocation_is_released_after_publication(self):
        with self.create(pool=128) as s:
            s._writing_generation=s.generation+1
            orphan=s._alloc_object(m.K_DATA,b'orphan');s.checkpoint()
            self.assertNotIn(tuple(orphan),s._pending);self.assertNotIn(tuple(orphan),s._cache)
            self.assertTrue(set(orphan[:2])<=set(s._free))
    def test_reference_metadata_exception_fences_after_durable_publication(self):
        with self.create() as s:
            s.transact({'/a':b'x'},'one')
            with mock.patch.object(s,'_release',side_effect=RuntimeError('RAM reference failure')):
                with self.assertRaises(RuntimeError):s.checkpoint()
            self.assertTrue(s.fenced)
        with m.PageStore(self.path,writable=False) as s:self.assertEqual(s.get('/a'),b'x')
    def test_unchanged_subtree_family_context_rejected(self):
        with self.create({'/a':b'old'}) as s:
            old_files=s.files_root;original=m.PageStore._update_tree
            def wrong_family(instance,desc,family,changes,depth=0):
                return old_files if family=='tokens' else original(instance,desc,family,changes,depth)
            s.reset_stats()
            s.transact({'/a':b'new'},'bad');s.reset_stats()
            with mock.patch.object(m.PageStore,'_update_tree',wrong_family):
                with self.assertRaises(m.InvalidImage):s.checkpoint_plan()
            self.assertEqual(s.stats['write_calls'],0);self.assertEqual(s.epoch,1)
            self.assertEqual(s.get('/a'),b'new')
    def test_unchanged_blob_cannot_alias_another_file_owner(self):
        with self.create({'/a':bytes(8000)}) as s:
            value=m.unpack_json(s._read_object(s.files_root,m.K_TRIE))['entries']['/a'];s.reset_stats()
            s.transact({'/b':b'offer'},'bad');s.reset_stats()
            with mock.patch.object(m.PageStore,'_file_value',return_value=value):
                with self.assertRaises(m.InvalidImage):s.checkpoint_plan()
            self.assertEqual(s.stats['write_calls'],0);self.assertEqual(s.query('bad')['epoch'],1)
    def test_nonlive_stale_object_cannot_be_resurrected(self):
        with self.create({'/a':b'old'}) as s:
            stale=s.files_root;s.transact({'/a':b'new'},'one');s.checkpoint()
            self.assertNotIn(tuple(stale),s._refs);original=m.PageStore._update_tree
            def stale_files(instance,desc,family,changes,depth=0):
                return stale if family=='files' else original(instance,desc,family,changes,depth)
            s.reset_stats()
            s.transact({'/a':b'latest'},'two');s.reset_stats()
            with mock.patch.object(m.PageStore,'_update_tree',stale_files):
                with self.assertRaises(m.InvalidImage):s.checkpoint_plan()
            self.assertEqual(s.stats['write_calls'],0);self.assertEqual(s.get('/a'),b'latest')
    def test_recovery_builds_references_once(self):
        with self.create({'/a':bytes(8000)}) as s:s.transact({'/a':b'x'},'one');s.checkpoint()
        with m.PageStore(self.path) as s:
            self.assertEqual(s.stats['full_graph_scans'],1);self.assertEqual(s.stats['pool_rebuilds'],1)
            self.assertTrue(all(count==1 for count in s._refs.values()))
            s.transact({'/a':b'y'},'two');s.reset_stats();s.checkpoint()
            self.assertEqual(s.stats['full_graph_scans'],0);self.assertEqual(s.stats['pool_rebuilds'],0)
    def test_epoch_exhaustion_no_io(self):
        with self.create() as s:
            s.epoch=m.MAX_U64;s.reset_stats()
            with self.assertRaises(m.StoreError):s.transact({'/a':b'x'},'one')
            self.assertEqual(s.stats['write_calls'],0)

    def test_lazy_heap_order_is_exact_and_nondestructive(self):
        import heapq,random
        rng=random.Random(1345)
        for n in (0,1,2,7,100,1000):
            heap=rng.sample(range(10000),n);heapq.heapify(heap);before=list(heap)
            self.assertEqual(list(m.PageStore._heap_order(heap)),sorted(before));self.assertEqual(heap,before)
    def test_admission_and_plan_query_do_not_write_or_reserve(self):
        with self.create({'/a':b'old'}) as s:
            free=list(s._free);owners=dict(s._block_owner);refs=dict(s._refs);s.reset_stats()
            s.transact({'/a':b'new'},'offer')
            self.assertEqual(s._free,free);self.assertEqual(s._block_owner,owners);self.assertEqual(s._refs,refs)
            calls=s.stats['write_calls'];forces=s.stats['fsync_calls'];plans=s.stats['admission_plans']
            answer=s.checkpoint_plan(include_writes=True)
            self.assertGreater(answer['physical_blocks'],0)
            self.assertEqual(s.stats['write_calls'],calls);self.assertEqual(s.stats['fsync_calls'],forces)
            self.assertEqual(s.stats['admission_plans'],plans+1)
    def test_checkpoint_executes_exact_admitted_bytes_without_rebuild(self):
        with self.create({'/a':b'old'}) as s:
            s.transact({'/a':bytes(9000),'/b':b'inline'},'offer')
            plan=s.checkpoint_plan(include_writes=True);writes=[];boundaries=[];original_write=s._pwrite;original_sync=s._sync
            def write(raw,offset):writes.append((offset,bytes(raw)));return original_write(raw,offset)
            def sync():boundaries.append(len(writes));return original_sync()
            with mock.patch.object(s,'_prepare_checkpoint_plan',side_effect=AssertionError('must use admitted plan')):
                with mock.patch.object(s,'_pwrite',write),mock.patch.object(s,'_sync',sync):s.checkpoint()
            self.assertEqual(tuple(writes),plan['writes']);self.assertEqual(tuple(boundaries),plan['force_boundaries'])
            self.assertEqual(sum(len(raw) for _,raw in writes),plan['bytes_written'])
    def test_rejected_offer_drains_previous_certified_window(self):
        with self.create(pool=32) as s:
            s.transact({'/a':b'fits'},'ack');before=s.checkpoint_plan(include_writes=True)
            with self.assertRaises(m.AdmissionRejected):s.transact({'/b':bytes(45000)},'reject')
            self.assertEqual(s.get('/a'),b'fits');self.assertIsNone(s.query('reject'));s.checkpoint()
            self.assertFalse(s.fenced)
    def test_recovery_recompiles_exact_acked_tail(self):
        with self.create() as s:s.transact({'/a':bytes(8000)},'ack')
        with m.PageStore(self.path) as s:
            self.assertEqual(s.checkpoint_plan()['epoch'],1);s.checkpoint()
            self.assertEqual(s.get('/a'),bytes(8000));self.assertEqual(s.query('ack')['epoch'],1)
    def test_readonly_plan_query_has_no_writes(self):
        with self.create() as s:s.transact({'/a':b'x'},'ack')
        before=self.path.read_bytes()
        with m.PageStore(self.path,writable=False) as s:
            self.assertEqual(s.checkpoint_plan()['epoch'],1);self.assertEqual(s.stats['write_calls'],0)
        self.assertEqual(self.path.read_bytes(),before)
    def test_caller_dictionary_changes_do_not_change_admitted_intent(self):
        with self.create() as s:
            request={'/a':b'original'};preview=s._reservation_preview
            def changed(*args):request['/a']=b'changed-after-validation';return preview(*args)
            with mock.patch.object(s,'_reservation_preview',changed):s.transact(request,'ack')
            self.assertEqual(s.get('/a'),b'original');s.checkpoint();self.assertEqual(s.get('/a'),b'original')
    def test_admitted_plan_holds_after_multiple_overwrites(self):
        with self.create({'/a':b'initial'},pool=256) as s:
            for i in range(40):
                s.transact({'/a':bytes([i])*((i%5)*1000+10)},f'token-{i}')
                self.assertEqual(s.checkpoint_plan()['epoch'],i+1)
            s.checkpoint();self.assertEqual(s.get('/a'),bytes([39])*4010)
    def test_fast_admissions_do_not_compile_pending_window(self):
        with self.create({f'/f{i}':bytes(128) for i in range(200)},pool=1024) as s:
            s.reset_stats()
            with mock.patch.object(s,'_prepare_checkpoint_plan',side_effect=AssertionError('fast path recompiled')):
                for i in range(64):s.transact({f'/f{i}':bytes([i])*128},f'fast-{i}')
            summary=s.admission_reservation()
            self.assertEqual(summary['certificate_kind'],'upper_bound')
            self.assertTrue(summary['tail_certified']);self.assertEqual(s.stats['reservation_fast_accepts'],64)
            self.assertEqual(s.stats['admission_plans'],0)
            self.assertLessEqual(len(s._prepare_checkpoint_plan()['dependency_writes']),summary['reserved_upper_blocks'])
            s.checkpoint()
    def test_symbolic_bound_dominates_mixed_exact_plans(self):
        import random
        rng=random.Random(7047)
        with self.create({f'/f{i}':rng.randbytes(128) for i in range(300)},pool=2048) as s:
            for i in range(120):
                changes={f'/f{rng.randrange(350)}':None if i%9==0 else rng.randbytes((0,128,256,257,3992,8000)[i%6])}
                s.transact(changes,f'mixed-{i}')
                if i%7==0:
                    bound=s.admission_reservation()['reserved_upper_blocks']
                    actual=len(s._prepare_checkpoint_plan()['dependency_writes'])
                    self.assertLessEqual(actual,bound)
                if i%30==29:s.checkpoint()
    def test_blob_credit_is_replaced_not_accumulated(self):
        with self.create(pool=256) as s:
            s.transact({'/a':bytes(30000)},'big');large=s.admission_reservation()['reserved_upper_blocks']
            s.transact({'/a':b'small'},'small');small=s.admission_reservation()['reserved_upper_blocks']
            self.assertGreater(large,small+10)
            self.assertEqual(s._reservation_blob_pages['/a'],0);s.checkpoint()
    def test_loose_bound_uses_exact_fallback_without_false_refusal(self):
        initial={};used=set()
        for i in range(1000):
            key=f'/p{i:04d}/'+('x'*900);nib=m.hash_key(key)[0]
            if nib not in used:initial[key]=bytes(256);used.add(nib)
            if len(initial)==4:break
        with self.create(initial,pool=16) as s:
            self.assertEqual(len(s._free),4);key=next(iter(initial));s.reset_stats()
            s.transact({key:initial[key]},'same')
            self.assertEqual(s.stats['reservation_exact_fallbacks'],1)
            self.assertEqual(s.admission_reservation()['certificate_kind'],'exact_plan')
            self.assertGreater(s.admission_reservation()['reserved_upper_blocks'],len(s._free))
            self.assertEqual(s.checkpoint_plan()['physical_blocks'],4);s.checkpoint()
    def test_reservation_failure_does_not_adopt_proposal(self):
        import copy
        with self.create({'/a':b'old'},pool=256) as s:
            s.transact({'/a':b'accepted'},'one');before=copy.deepcopy(s._reservation_cells)
            bound=s._reservation_logical;s.reset_stats()
            with mock.patch.object(m.PageStore,'_budget_update',side_effect=MemoryError('symbolic OOM')):
                with self.assertRaises(MemoryError):s.transact({'/a':b'offer'},'two')
            self.assertEqual(s._reservation_cells,before);self.assertEqual(s._reservation_logical,bound)
            self.assertEqual(s.stats['write_calls'],0);self.assertIsNone(s.query('two'));self.assertFalse(s.fenced)
            s.checkpoint()
    def test_generation_exhaustion_rejects_fast_offer_without_io(self):
        with self.create(pool=256) as s:
            s.generation=m.MAX_U64;s.reset_stats()
            with self.assertRaises(m.StoreError):s.transact({'/a':b'no'},'exhausted')
            self.assertEqual(s.stats['write_calls'],0);self.assertEqual(s.epoch,0)
    def test_bound_reconstructed_after_reopen(self):
        with self.create({'/a':b'old'},pool=256) as s:
            s.transact({'/a':bytes(9000),'/b':b'new'},'accepted')
            bound=s.admission_reservation()['reserved_upper_blocks']
        with m.PageStore(self.path) as s:
            self.assertEqual(s.admission_reservation()['reserved_upper_blocks'],bound)
            self.assertLessEqual(s.checkpoint_plan()['physical_blocks'],bound);s.checkpoint()
    def test_format_maximum_reference_containers_fit(self):
        self.assertLessEqual(len(m.canonical({'family':'tokens','type':'branch','depth':63,'children':{n:m.BOUND_DESC for n in m.HEX}})),m.PAGE_PAYLOAD)
        self.assertLessEqual(len(m.canonical({'length':m.MAX_CAPSULE,'digest':'f'*64,'chunks':[m.BOUND_DESC]*17})),m.PAGE_PAYLOAD)
    def test_weighted_budget_never_serializes_nonempty_symbolic_leaf(self):
        real=m.canonical
        def guarded(obj):
            if isinstance(obj,dict) and obj.get('type')=='leaf' and obj.get('entries'):
                raise AssertionError('whole symbolic leaf serialized')
            return real(obj)
        with self.create(pool=2048) as store:
            with mock.patch.object(m,'canonical',side_effect=guarded), \
                 mock.patch.object(store,'_prepare_checkpoint_plan',side_effect=AssertionError('late exact plan')), \
                 mock.patch.object(store,'_reservation_count',side_effect=AssertionError('whole cell recounted')):
                for i in range(32):
                    store.transact({f'/new/{i:03d}/{j}':bytes([i])*128 for j in range(8)},f'weighted-{i}')
            bound=store.admission_reservation()['reserved_upper_blocks']
            self.assertGreater(store.stats['reservation_leaf_splits'],0)
            self.assertEqual(store.stats['reservation_fast_accepts'],32)
            self.assertLessEqual(len(store._prepare_checkpoint_plan()['dependency_writes']),bound)
            store.checkpoint()
    def test_equal_size_replacement_reuses_file_budget_identity(self):
        with self.create(pool=2048) as store:
            store.transact({f'/item/{i:03d}':bytes(128) for i in range(40)},'seed')
            anchor=store._reservation_route('files','/item/000')[0]
            previous=store._reservation_cells[anchor]['tree']
            store.transact({'/item/000':b'x'*128},'replace')
            self.assertIs(store._reservation_cells[anchor]['tree'],previous)
            store.checkpoint();self.assertEqual(store.get('/item/000'),b'x'*128)
    def test_partial_weighted_proposal_failure_preserves_accepted_tree(self):
        with self.create(pool=2048) as store:
            store.transact({'/old':b'accepted'},'accepted')
            before=dict(store._reservation_cells);budget=store._reservation_logical
            calls=0;update=store._budget_update
            def fail(family,node,key,weight,depth,hashed=None):
                nonlocal calls
                calls+=1
                if calls==2:raise MemoryError('second weighted edit')
                return update(family,node,key,weight,depth,hashed)
            store.reset_stats()
            with mock.patch.object(store,'_budget_update',side_effect=fail):
                with self.assertRaises(MemoryError):store.transact({'/new/1':b'a','/new/2':b'b'},'refused')
            self.assertEqual(store._reservation_cells,before);self.assertEqual(store._reservation_logical,budget)
            self.assertEqual(store.stats['write_calls'],0);self.assertEqual(store.epoch,1)
            self.assertIsNone(store.query('refused'));self.assertFalse(store.fenced)
            store.checkpoint()
    def test_weighted_leaf_byte_identity_for_escaped_published_values(self):
        paths=('/plain','/quote\"/line\n','/雪/😀','/'+chr(1)*500)
        with self.create(pool=1024) as store:
            for depth in (0,9,10,63,64):
                entries={path:{'inline':m.b64(bytes([i])*128)} for i,path in enumerate(paths)}
                weights={key:store._budget_published_weight('files',key,value) for key,value in entries.items()}
                predicted=store._budget_leaf_bytes('files',depth,weights,sum(weights.values()))
                self.assertEqual(predicted,len(m.canonical({'family':'files','type':'leaf','depth':depth,'entries':entries})))
            for epoch in (1,9,10,m.MAX_U64):
                token='receipt_09';value=[epoch,'a'*64]
                self.assertEqual(store._budget_published_weight('tokens',token,value),len(m.canonical(token))+1+len(m.canonical(value)))
            desc=[0,m.MAX_POOL_BLOCKS-1,m.MAX_U64,m.K_BLOB,m.PAGE_PAYLOAD,'f'*64]
            self.assertEqual(store._budget_published_weight('files',paths[2],{'blob':desc}),len(m.canonical(paths[2]))+1+len(m.canonical({'blob':desc})))
    def test_published_entry_weights_are_computed_once_per_cell(self):
        with self.create({'/same':bytes(128)},pool=512) as store:
            store.transact({'/same':b'a'*128},'first')
            with mock.patch.object(store,'_budget_published_weight',side_effect=AssertionError('published cell reweighted')):
                for i in range(12):store.transact({'/same':bytes([i])*128},f'overwrite-{i}')
            store.checkpoint()
if __name__=='__main__':unittest.main()