diff --git a/examples/prosemirror-history.js b/examples/prosemirror-history.js
index 33106b7d..d84f3fbf 100644
--- a/examples/prosemirror-history.js
+++ b/examples/prosemirror-history.js
@@ -3,8 +3,8 @@ import { Plugin } from 'prosemirror-state'
 import crel from 'crel'
 import * as Y from '../src/index.js'
 import { prosemirrorPluginKey } from 'y-prosemirror'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
 import * as historyProtocol from 'y-protocols/history.js'
 
 const niceColors = ['#3cb44b', '#4363d8', '#f58231', '#911eb4', '#46f0f0', '#f032e6', '#bcf60c', '#008080', '#9a6324', '#800000', '#808000', '#000075', '#808080']
diff --git a/package.json b/package.json
index 90d421b4..57b2197d 100644
--- a/package.json
+++ b/package.json
@@ -6,7 +6,8 @@
   "module": "./dist/yjs.mjs'",
   "sideEffects": false,
   "scripts": {
-    "test": "npm run lint && npm run dist && node ./dist/tests.js --repitition-time 10000",
+    "test": "npm run lint && npm run dist && node ./dist/tests.js --repitition-time 50",
+    "test-exhaustive": "npm run lint && npm run dist && node ./dist/tests.js --repitition-time 10000",
     "dist": "rm -rf dist examples/build && PRODUCTION=1 rollup -c",
     "watch": "rollup -wc",
     "lint": "standard",
diff --git a/rollup.config.js b/rollup.config.js
index 803c4e7e..7fce1eea 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -56,7 +56,7 @@ export default [{
     sourcemap: true,
     paths: path => {
       if (/^funlib\//.test(path)) {
-        return `funlib/dist${path.slice(6)}`
+        return `lib0/dist${path.slice(6)}`
       }
       return path
     }
diff --git a/src/structs/Delete.js b/src/structs/Delete.js
index 34698b2a..835dac09 100644
--- a/src/structs/Delete.js
+++ b/src/structs/Delete.js
@@ -5,8 +5,8 @@
 import { getStructReference } from 'y-protocols/sync.js'
 import * as ID from '../utils/ID.js'
 import { writeStructToTransaction } from '../utils/structEncoding.js'
-import * as decoding from 'funlib/decoding.js'
-import * as encoding from 'funlib/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+import * as encoding from 'lib0/encoding.js'
 // import { Item } from './Item.js' // eslint-disable-line
 // import { Y } from '../utils/Y.js' // eslint-disable-line
 import { deleteItemRange } from '../utils/structManipulation.js'
diff --git a/src/structs/GC.js b/src/structs/GC.js
index a7034fe4..4821c9da 100644
--- a/src/structs/GC.js
+++ b/src/structs/GC.js
@@ -5,8 +5,8 @@
 import { getStructReference } from 'y-protocols/sync.js'
 import * as ID from '../utils/ID.js'
 import { writeStructToTransaction } from '../utils/structEncoding.js'
-import * as decoding from 'funlib/decoding.js'
-import * as encoding from 'funlib/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+import * as encoding from 'lib0/encoding.js'
 // import { Y } from '../utils/Y.js' // eslint-disable-line
 
 // TODO should have the same base class as Item
diff --git a/src/structs/Item.js b/src/structs/Item.js
index 885fe397..80efc4c1 100644
--- a/src/structs/Item.js
+++ b/src/structs/Item.js
@@ -7,8 +7,8 @@ import * as ID from '../utils/ID.js'
 import { Delete } from './Delete.js'
 import { writeStructToTransaction } from '../utils/structEncoding.js'
 import { GC } from './GC.js'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
 
 /**
  * @private
diff --git a/src/structs/ItemBinary.js b/src/structs/ItemBinary.js
index b3714c6e..165d125e 100644
--- a/src/structs/ItemBinary.js
+++ b/src/structs/ItemBinary.js
@@ -6,8 +6,8 @@
 
 import { Item } from './Item.js'
 import * as stringify from 'y-protocols/utils/structStringify.js'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
 import { Y } from '../utils/Y.js' // eslint-disable-line
 
 export class ItemBinary extends Item {
diff --git a/src/structs/ItemEmbed.js b/src/structs/ItemEmbed.js
index 551de984..1ad0fa5c 100644
--- a/src/structs/ItemEmbed.js
+++ b/src/structs/ItemEmbed.js
@@ -4,8 +4,8 @@
 
 import { Item } from './Item.js'
 import * as stringify from 'y-protocols/utils/structStringify.js'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
 import { Y } from '../utils/Y.js'  // eslint-disable-line
 
 export class ItemEmbed extends Item {
diff --git a/src/structs/ItemFormat.js b/src/structs/ItemFormat.js
index d9472068..9f005f7e 100644
--- a/src/structs/ItemFormat.js
+++ b/src/structs/ItemFormat.js
@@ -4,8 +4,8 @@
 
 import { Item } from './Item.js'
 import * as stringify from 'y-protocols/utils/structStringify.js'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
 import { Y } from '../utils/Y.js' // eslint-disable-line
 
 export class ItemFormat extends Item {
diff --git a/src/structs/ItemJSON.js b/src/structs/ItemJSON.js
index 5ccdbaf2..88b976e8 100644
--- a/src/structs/ItemJSON.js
+++ b/src/structs/ItemJSON.js
@@ -4,8 +4,8 @@
 
 import { Item, splitHelper } from './Item.js'
 import * as stringify from 'y-protocols/utils/structStringify.js'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
 import { Y } from '../utils/Y.js' // eslint-disable-line
 
 export class ItemJSON extends Item {
diff --git a/src/structs/ItemString.js b/src/structs/ItemString.js
index 753be26f..84d2d850 100644
--- a/src/structs/ItemString.js
+++ b/src/structs/ItemString.js
@@ -4,8 +4,8 @@
 
 import { Item, splitHelper } from './Item.js'
 import * as stringify from 'y-protocols/utils/structStringify.js'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
 import { Y } from '../utils/Y.js' // eslint-disable-line
 
 export class ItemString extends Item {
diff --git a/src/types/YXmlElement.js b/src/types/YXmlElement.js
index ee1225ed..0a73731e 100644
--- a/src/types/YXmlElement.js
+++ b/src/types/YXmlElement.js
@@ -3,8 +3,8 @@
  */
 
 import { YMap } from './YMap.js'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
 import { Y } from '../utils/Y.js' // eslint-disable-line
 import { YArray } from './YArray.js'
 import { YXmlEvent } from './YXmlEvent.js'
diff --git a/src/types/YXmlHook.js b/src/types/YXmlHook.js
index cb287ffd..e41c3536 100644
--- a/src/types/YXmlHook.js
+++ b/src/types/YXmlHook.js
@@ -3,8 +3,8 @@
  */
 
 import { YMap } from './YMap.js'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
 import { Y } from '../utils/Y.js' // eslint-disable-line
 
 /**
diff --git a/src/utils/DeleteStore.js b/src/utils/DeleteStore.js
index 355fbc73..f48c9534 100644
--- a/src/utils/DeleteStore.js
+++ b/src/utils/DeleteStore.js
@@ -2,7 +2,7 @@
  * @module utils
  */
 
-import { Tree } from 'funlib/tree.js'
+import { Tree } from 'lib0/tree.js'
 import * as ID from './ID.js'
 
 export class DSNode {
diff --git a/src/utils/ID.js b/src/utils/ID.js
index bb8d82fa..6548bd3b 100644
--- a/src/utils/ID.js
+++ b/src/utils/ID.js
@@ -3,8 +3,8 @@
  */
 
 import { getStructReference } from 'y-protocols/sync.js'
-import * as decoding from 'funlib/decoding.js'
-import * as encoding from 'funlib/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+import * as encoding from 'lib0/encoding.js'
 
 export class ID {
   constructor (user, clock) {
diff --git a/src/utils/OperationStore.js b/src/utils/OperationStore.js
index a64300b1..04a6b6a6 100644
--- a/src/utils/OperationStore.js
+++ b/src/utils/OperationStore.js
@@ -2,7 +2,7 @@
  * @module utils
  */
 
-import { Tree } from 'funlib/tree.js'
+import { Tree } from 'lib0/tree.js'
 import * as ID from '../utils/ID.js'
 import { getStruct } from 'y-protocols/sync.js'
 import { GC } from '../structs/GC.js'
diff --git a/src/utils/Transaction.js b/src/utils/Transaction.js
index 269d7d07..3cea6b9d 100644
--- a/src/utils/Transaction.js
+++ b/src/utils/Transaction.js
@@ -2,7 +2,7 @@
  * @module utils
  */
 
-import * as encoding from 'funlib/encoding.js'
+import * as encoding from 'lib0/encoding.js'
 
 /**
  * A transaction is created for every change on the Yjs model. It is possible
diff --git a/src/utils/Y.js b/src/utils/Y.js
index 8079f44d..ec2f90e9 100644
--- a/src/utils/Y.js
+++ b/src/utils/Y.js
@@ -1,9 +1,9 @@
 import { DeleteStore } from './DeleteStore.js'
 import { OperationStore } from './OperationStore.js'
 import { StateStore } from './StateStore.js'
-import * as random from 'funlib/random.js'
+import * as random from 'lib0/random.js'
 import { createRootID } from './ID.js'
-import { Observable } from 'funlib/observable.js'
+import { Observable } from 'lib0/observable.js'
 import { Transaction } from './Transaction.js'
 
 /**
diff --git a/src/utils/integrateRemoteStructs.js b/src/utils/integrateRemoteStructs.js
index 4b62a6d6..07f42851 100644
--- a/src/utils/integrateRemoteStructs.js
+++ b/src/utils/integrateRemoteStructs.js
@@ -3,7 +3,7 @@
  */
 
 import { getStruct } from 'y-protocols/sync.js'
-import * as decoding from 'funlib/decoding.js'
+import * as decoding from 'lib0/decoding.js'
 import { GC } from '../structs/GC.js'
 import { Y } from '../utils/Y.js' // eslint-disable-line
 import { Item } from '../structs/Item.js' // eslint-disable-line
diff --git a/tests/DeleteStore.tests.js b/tests/DeleteStore.tests.js
index 1e13d476..d947a11a 100644
--- a/tests/DeleteStore.tests.js
+++ b/tests/DeleteStore.tests.js
@@ -1,5 +1,5 @@
-import * as prng from 'funlib/prng.js'
-import * as t from 'funlib/testing.js'
+import * as prng from 'lib0/prng.js'
+import * as t from 'lib0/testing.js'
 import { DeleteStore } from '../src/utils/DeleteStore.js'
 import * as ID from '../src/utils/ID.js'
 
@@ -58,8 +58,8 @@ export const testRepeatDeleteStoreTests = tc => {
   const ds = new DeleteStore()
   const dsArray = []
   for (let i = 0; i < 200; i++) {
-    const pos = prng.int32(gen, 0, 10)
-    const len = prng.int32(gen, 0, 4)
+    const pos = prng.int31(gen, 0, 10)
+    const len = prng.int31(gen, 0, 4)
     const gc = prng.bool(gen)
     ds.mark(ID.createID(0, pos), len, gc)
     for (let j = 0; j < len; j++) {
@@ -72,7 +72,7 @@ export const testRepeatDeleteStoreTests = tc => {
       dsArray[i] = null
     }
   }
-  t.compareArrays(dsToArray(ds), dsArray, 'Expected DS result')
+  t.compareArrays(dsToArray(ds), dsArray)
   let size = 0
   let lastEl = null
   for (let i = 0; i < dsArray.length; i++) {
@@ -82,5 +82,5 @@ export const testRepeatDeleteStoreTests = tc => {
     }
     lastEl = el
   }
-  t.assert(size === ds.length, 'DS sizes match')
+  t.assert(size === ds.length)
 }
diff --git a/tests/helper.js b/tests/helper.js
index 4b76d359..d8235d86 100644
--- a/tests/helper.js
+++ b/tests/helper.js
@@ -5,11 +5,11 @@ import { ItemString } from '../src/structs/ItemString.js'
 import { defragmentItemContent } from '../src/utils/defragmentItemContent.js'
 import Quill from 'quill'
 import { GC } from '../src/structs/GC.js'
-import * as random from 'funlib/prng.js'
+import * as random from 'lib0/prng.js'
 import * as syncProtocol from 'y-protocols/sync.js'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
-import { createMutex } from 'funlib/mutex.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
+import { createMutex } from 'lib0/mutex.js'
 import { QuillBinding } from 'y-quill'
 import { DomBinding } from 'y-dom'
 
diff --git a/tests/index.js b/tests/index.js
index 25f10007..e0d0a09f 100644
--- a/tests/index.js
+++ b/tests/index.js
@@ -1,7 +1,7 @@
 
-import { runTests } from 'funlib/testing.js'
-import { isBrowser } from 'funlib/environment.js'
-import * as log from 'funlib/logging.js'
+import { runTests } from 'lib0/testing.js'
+import { isBrowser } from 'lib0/environment.js'
+import * as log from 'lib0/logging.js'
 import * as deleteStore from './DeleteStore.tests.js'
 import * as array from './y-array.tests.js'
 
diff --git a/tests/testHelper.js b/tests/testHelper.js
index ff81e159..4683212f 100644
--- a/tests/testHelper.js
+++ b/tests/testHelper.js
@@ -1,9 +1,9 @@
 import * as Y from '../src/index.js'
-import * as t from 'funlib/testing.js'
-import * as prng from 'funlib/prng.js'
-import { createMutex } from 'funlib/mutex.js'
-import * as encoding from 'funlib/encoding.js'
-import * as decoding from 'funlib/decoding.js'
+import * as t from 'lib0/testing.js'
+import * as prng from 'lib0/prng.js'
+import { createMutex } from 'lib0/mutex.js'
+import * as encoding from 'lib0/encoding.js'
+import * as decoding from 'lib0/decoding.js'
 import * as syncProtocol from 'y-protocols/sync.js'
 import { defragmentItemContent } from '../src/utils/defragmentItemContent.js'
 
@@ -331,21 +331,19 @@ export const compare = users => {
   })
   for (var i = 0; i < data.length - 1; i++) {
     // t.describe(`Comparing user${i} with user${i + 1}`)
-    t.compare(userArrayValues[i].length, users[i].get('array').length, 'array length correctly computed')
-    t.compare(userArrayValues[i], userArrayValues[i + 1], 'array types')
-    t.compare(userMapValues[i], userMapValues[i + 1], 'map types')
-    t.compare(userXmlValues[i], userXmlValues[i + 1], 'xml types')
-    t.compare(userTextValues[i].map(a => a.insert).join('').length, users[i].get('text').length, 'text length correctly computed')
-    t.compare(userTextValues[i], userTextValues[i + 1], 'text types')
-    t.compare(data[i].os, data[i + 1].os, 'os', customOSCompare)
-    t.compare(data[i].ds, data[i + 1].ds, 'ds', customOSCompare)
-    t.compare(data[i].ss, data[i + 1].ss, 'ss', customOSCompare)
+    t.compare(userArrayValues[i].length, users[i].get('array').length)
+    t.compare(userArrayValues[i], userArrayValues[i + 1])
+    t.compare(userMapValues[i], userMapValues[i + 1])
+    t.compare(userXmlValues[i], userXmlValues[i + 1])
+    t.compare(userTextValues[i].map(a => a.insert).join('').length, users[i].get('text').length)
+    t.compare(userTextValues[i], userTextValues[i + 1])
+    t.compare(data[i].os, data[i + 1].os, null, customOSCompare)
+    t.compare(data[i].ds, data[i + 1].ds, null, customOSCompare)
+    t.compare(data[i].ss, data[i + 1].ss, null, customOSCompare)
   }
-  users.forEach(user => {
-    if (user._missingStructs.size !== 0) {
-      t.fail('missing structs should be empty!')
-    }
-  })
+  users.forEach(user =>
+    t.assert(user._missingStructs.size === 0)
+  )
   users.map(u => u.destroy())
 }
 
@@ -354,20 +352,20 @@ export const applyRandomTests = (tc, mods, iterations) => {
   const result = init({ users: 5, prng: gen })
   const { testConnector, users } = result
   for (var i = 0; i < iterations; i++) {
-    if (prng.int32(gen, 0, 100) <= 2) {
+    if (prng.int31(gen, 0, 100) <= 2) {
       // 2% chance to disconnect/reconnect a random user
       if (prng.bool(gen)) {
         testConnector.disconnectRandom()
       } else {
         testConnector.reconnectRandom()
       }
-    } else if (prng.int32(gen, 0, 100) <= 1) {
+    } else if (prng.int31(gen, 0, 100) <= 1) {
       // 1% chance to flush all & garbagecollect
       // TODO: We do not gc all users as this does not work yet
       // await garbageCollectUsers(t, users)
       testConnector.flushAllMessages()
       // await users[0].db.emptyGarbageCollector() // TODO: reintroduce GC tests!
-    } else if (prng.int32(gen, 0, 100) <= 50) {
+    } else if (prng.int31(gen, 0, 100) <= 50) {
       // 50% chance to flush a random message
       testConnector.flushRandomMessage()
     }
diff --git a/tests/y-array.tests.js b/tests/y-array.tests.js
index fca47d4e..044bf8ac 100644
--- a/tests/y-array.tests.js
+++ b/tests/y-array.tests.js
@@ -1,18 +1,18 @@
 import { init, compare, applyRandomTests } from './testHelper.js'
 import * as Y from '../src/index.js'
-import * as t from 'funlib/testing.js'
-import * as prng from 'funlib/prng.js'
+import * as t from 'lib0/testing.js'
+import * as prng from 'lib0/prng.js'
 
 export const testDeleteInsert = tc => {
   const { users, array0 } = init(tc, { users: 2 })
   array0.delete(0, 0)
-  t.assert(true, 'Does not throw when deleting zero elements with position 0')
+  t.describe('Does not throw when deleting zero elements with position 0')
   t.fails(() => {
     array0.delete(1, 1)
-  }, 'Throws when deleting with an invalid position')
+  })
   array0.insert(0, ['A'])
   array0.delete(1, 0)
-  t.assert(true, 'Does not throw when deleting zero elements with valid position 1')
+  t.describe('Does not throw when deleting zero elements with valid position 1')
   compare(users)
 }
 
@@ -229,23 +229,23 @@ let arrayTransactions = [
     const yarray = user.define('array', Y.Array)
     var uniqueNumber = getUniqueNumber()
     var content = []
-    var len = prng.int32(gen, 1, 4)
+    var len = prng.int31(gen, 1, 4)
     for (var i = 0; i < len; i++) {
       content.push(uniqueNumber)
     }
-    var pos = prng.int32(gen, 0, yarray.length)
+    var pos = prng.int31(gen, 0, yarray.length)
     yarray.insert(pos, content)
   },
   function insertTypeArray (t, user, gen) {
     const yarray = user.define('array', Y.Array)
-    var pos = prng.int32(gen, 0, yarray.length)
+    var pos = prng.int31(gen, 0, yarray.length)
     yarray.insert(pos, [Y.Array])
     var array2 = yarray.get(pos)
     array2.insert(0, [1, 2, 3, 4])
   },
   function insertTypeMap (t, user, gen) {
     const yarray = user.define('array', Y.Array)
-    var pos = prng.int32(gen, 0, yarray.length)
+    var pos = prng.int31(gen, 0, yarray.length)
     yarray.insert(pos, [Y.Map])
     var map = yarray.get(pos)
     map.set('someprop', 42)
@@ -256,14 +256,14 @@ let arrayTransactions = [
     const yarray = user.define('array', Y.Array)
     var length = yarray.length
     if (length > 0) {
-      var somePos = prng.int32(gen, 0, length - 1)
-      var delLength = prng.int32(gen, 1, Math.min(2, length - somePos))
+      var somePos = prng.int31(gen, 0, length - 1)
+      var delLength = prng.int31(gen, 1, Math.min(2, length - somePos))
       if (yarray instanceof Y.Array) {
         if (prng.bool(gen)) {
           var type = yarray.get(somePos)
           if (type.length > 0) {
-            somePos = prng.int32(gen, 0, type.length - 1)
-            delLength = prng.int32(gen, 0, Math.min(2, type.length - somePos))
+            somePos = prng.int31(gen, 0, type.length - 1)
+            delLength = prng.int31(gen, 0, Math.min(2, type.length - somePos))
             type.delete(somePos, delLength)
           }
         } else {
diff --git a/tests/y-map.tests.js b/tests/y-map.tests.js
index 805acb0d..4a1febcf 100644
--- a/tests/y-map.tests.js
+++ b/tests/y-map.tests.js
@@ -1,7 +1,7 @@
 import { initArrays, compareUsers, applyRandomTests } from './helper.js'
 import * as Y from '../src/index.js'
 import { test, proxyConsole } from 'cutest'
-import * as random from 'funlib/prng/prng.js'
+import * as random from 'lib0/prng/prng.js'
 
 proxyConsole()