diff --git a/bindings/Binding.js b/bindings/Binding.js
index 34addfa3..5a97eb08 100644
--- a/bindings/Binding.js
+++ b/bindings/Binding.js
@@ -1,5 +1,5 @@
 
-import { createMutex } from '../../lib/mutex.js'
+import { createMutex } from '../lib/mutex.js'
 
 /**
  * Abstract class for bindings.
diff --git a/bindings/DomBinding/DomBinding.js b/bindings/DomBinding/DomBinding.js
index fc68179c..d486ffc7 100644
--- a/bindings/DomBinding/DomBinding.js
+++ b/bindings/DomBinding/DomBinding.js
@@ -1,6 +1,6 @@
 /* global MutationObserver, getSelection */
 
-import { fromRelativePosition } from '../../Util/relativePosition.js'
+import { fromRelativePosition } from '../../src/Util/relativePosition.js'
 import Binding from '../Binding.js'
 import { createAssociation, removeAssociation } from './util.js'
 import { beforeTransactionSelectionFixer, afterTransactionSelectionFixer, getCurrentRelativeSelection } from './selection.js'
@@ -121,8 +121,15 @@ export default class DomBinding extends Binding {
     createAssociation(this, target, type)
   }
 
+  flushDomChanges () {
+    this._domObserver(this._mutationObserver.takeRecords())
+  }
+
   /**
-   * NOTE: currently does not apply filter to existing elements!
+   * NOTE:
+   * * does not apply filter to existing elements!
+   * * only guarantees that changes are filtered locally. Remote sites may see different content.
+   *
    * @param {DomFilter} filter The filter function to use from now on.
    */
   setFilter (filter) {
diff --git a/bindings/DomBinding/domObserver.js b/bindings/DomBinding/domObserver.js
index 0c27443b..b162b288 100644
--- a/bindings/DomBinding/domObserver.js
+++ b/bindings/DomBinding/domObserver.js
@@ -1,11 +1,11 @@
 
-import YXmlHook from '../../Types/YXml/YXmlHook.js'
+import YXmlHook from '../../src/Types/YXml/YXmlHook.js'
 import {
   iterateUntilUndeleted,
   removeAssociation,
   insertNodeHelper } from './util.js'
-import diff from '../../../lib/simpleDiff.js'
-import YXmlFragment from '../../Types/YXml/YXmlFragment.js'
+import diff from '../../lib/simpleDiff.js'
+import YXmlFragment from '../../src/Types/YXml/YXmlFragment.js'
 
 /**
  * 1. Check if any of the nodes was deleted
diff --git a/src/Struct/Item.js b/src/Struct/Item.js
index c344ba8a..081c0188 100644
--- a/src/Struct/Item.js
+++ b/src/Struct/Item.js
@@ -47,10 +47,12 @@ export function splitHelper (y, a, b, diff) {
     o = o._right
   }
   y.os.put(b)
-  if (y._transaction.newTypes.has(a)) {
-    y._transaction.newTypes.add(b)
-  } else if (y._transaction.deletedStructs.has(a)) {
-    y._transaction.deletedStructs.add(b)
+  if (y._transaction !== null) {
+    if (y._transaction.newTypes.has(a)) {
+      y._transaction.newTypes.add(b)
+    } else if (y._transaction.deletedStructs.has(a)) {
+      y._transaction.deletedStructs.add(b)
+    }
   }
 }
 
@@ -117,7 +119,7 @@ export default class Item {
    */
   _copy () {
     const C = this.constructor
-    return C()
+    return new C()
   }
 
   /**
diff --git a/src/protocols/syncProtocol.js b/src/protocols/syncProtocol.js
index c779bcc4..7a8ceae8 100644
--- a/src/protocols/syncProtocol.js
+++ b/src/protocols/syncProtocol.js
@@ -54,7 +54,7 @@ export const stringifyDeleteSet = (decoder) => {
   const dsLength = decoding.readUint32(decoder)
   for (let i = 0; i < dsLength; i++) {
     str += ' -' + decoding.readVarUint(decoder) + ':\n' // decodes user
-    const dvLength = decoding.readVarUint(decoder)
+    const dvLength = decoding.readUint32(decoder)
     for (let j = 0; j < dvLength; j++) {
       str += `clock: ${decoding.readVarUint(decoder)}, length: ${decoding.readVarUint(decoder)}, gc: ${decoding.readUint8(decoder) === 1}\n`
     }
@@ -192,8 +192,8 @@ export const readDeleteSet = (decoder, y) => {
  */
 export const stringifyStateSet = decoder => {
   let s = 'State Set: '
-  readStateSet(decoder).forEach((user, userState) => {
-    s += `(${user}: ${userState}), `
+  readStateSet(decoder).forEach((clock, user) => {
+    s += `(${user}: ${clock}), `
   })
   return s
 }
@@ -209,7 +209,7 @@ export const writeStateSet = (encoder, y) => {
   // write as fixed-size number to stay consistent with the other encode functions.
   // => anytime we write the number of objects that follow, encode as fixed-size number.
   encoding.writeUint32(encoder, state.size)
-  state.forEach((user, clock) => {
+  state.forEach((clock, user) => {
     encoding.writeVarUint(encoder, user)
     encoding.writeVarUint(encoder, clock)
   })
@@ -317,7 +317,9 @@ export const writeStructs = (encoder, y, ss) => {
       const overlappingLeft = y.os.findPrev(minBound)
       const rightID = overlappingLeft === null ? null : overlappingLeft._id
       if (rightID !== null && rightID.user === user && rightID.clock + overlappingLeft._length > clock) {
-        const struct = overlappingLeft._clonePartial(clock - rightID.clock)
+        // TODO: only write partial content (only missing content)
+        // const struct = overlappingLeft._clonePartial(clock - rightID.clock)
+        const struct = overlappingLeft
         struct._toBinary(encoder)
         len++
       }
diff --git a/test/encode-decode.tests.js b/test/encode-decode.tests.js
index ad668245..f0c37854 100644
--- a/test/encode-decode.tests.js
+++ b/test/encode-decode.tests.js
@@ -13,8 +13,8 @@ function testEncoding (t, write, read, val) {
   t.compare(val, result, 'Compare results')
 }
 
-const writeVarUint = (encoder, val) => encoder.writeVarUint(val)
-const readVarUint = decoder => decoder.readVarUint()
+const writeVarUint = (encoder, val) => encoding.writeVarUint(encoder, val)
+const readVarUint = decoder => decoding.readVarUint(decoder)
 
 test('varUint 1 byte', async function varUint1 (t) {
   testEncoding(t, writeVarUint, readVarUint, 42)
@@ -46,8 +46,8 @@ test('varUint random user id', async function varUintRandomUserId (t) {
   testEncoding(t, writeVarUint, readVarUint, generateRandomUint32())
 })
 
-const writeVarString = (encoder, val) => encoder.writeVarString(val)
-const readVarString = decoder => decoder.readVarString()
+const writeVarString = (encoder, val) => encoding.writeVarString(encoder, val)
+const readVarString = decoder => decoding.readVarString(decoder)
 
 test('varString', async function varString (t) {
   testEncoding(t, writeVarString, readVarString, 'hello')
diff --git a/test/y-array.tests.js b/test/y-array.tests.js
index 26a0d909..8c57444b 100644
--- a/test/y-array.tests.js
+++ b/test/y-array.tests.js
@@ -65,6 +65,7 @@ test('insertions work in late sync', async function array4 (t) {
   array2.insert(1, ['user2'])
   await users[1].connect()
   await users[2].connect()
+  testConnector.flushAllMessages()
   await compareUsers(t, users)
 })
 
@@ -215,7 +216,7 @@ function getUniqueNumber () {
 
 var arrayTransactions = [
   function insert (t, user, prng) {
-    const yarray = user.get('array', Y.Array)
+    const yarray = user.define('array', Y.Array)
     var uniqueNumber = getUniqueNumber()
     var content = []
     var len = random.int32(prng, 1, 4)
@@ -226,14 +227,14 @@ var arrayTransactions = [
     yarray.insert(pos, content)
   },
   function insertTypeArray (t, user, prng) {
-    const yarray = user.get('array', Y.Array)
+    const yarray = user.define('array', Y.Array)
     var pos = random.int32(prng, 0, yarray.length)
     yarray.insert(pos, [Y.Array])
     var array2 = yarray.get(pos)
     array2.insert(0, [1, 2, 3, 4])
   },
   function insertTypeMap (t, user, prng) {
-    const yarray = user.get('array', Y.Array)
+    const yarray = user.define('array', Y.Array)
     var pos = random.int32(prng, 0, yarray.length)
     yarray.insert(pos, [Y.Map])
     var map = yarray.get(pos)
@@ -242,7 +243,7 @@ var arrayTransactions = [
     map.set('someprop', 44)
   },
   function _delete (t, user, prng) {
-    const yarray = user.get('array', Y.Array)
+    const yarray = user.define('array', Y.Array)
     var length = yarray.length
     if (length > 0) {
       var somePos = random.int32(prng, 0, length - 1)
diff --git a/test/y-map.tests.js b/test/y-map.tests.js
index ffb3b8c5..e3518383 100644
--- a/test/y-map.tests.js
+++ b/test/y-map.tests.js
@@ -50,7 +50,7 @@ test('Basic get&set of Map property (converge via sync)', async function map1 (t
   testConnector.flushAllMessages()
 
   for (let user of users) {
-    var u = user.get('map', Y.Map)
+    var u = user.define('map', Y.Map)
     t.compare(u.get('stuff'), 'stuffy')
     t.assert(u.get('undefined') === undefined, 'undefined')
     t.compare(u.get('null'), null, 'null')
@@ -94,7 +94,7 @@ test('Basic get&set of Map property (converge via update)', async function map5
   testConnector.flushAllMessages()
 
   for (let user of users) {
-    var u = user.get('map', Y.Map)
+    var u = user.define('map', Y.Map)
     t.compare(u.get('stuff'), 'stuffy')
   }
   await compareUsers(t, users)
@@ -108,7 +108,7 @@ test('Basic get&set of Map property (handle conflict)', async function map6 (t)
   testConnector.flushAllMessages()
 
   for (let user of users) {
-    var u = user.get('map', Y.Map)
+    var u = user.define('map', Y.Map)
     t.compare(u.get('stuff'), 'c0')
   }
   await compareUsers(t, users)
@@ -121,7 +121,7 @@ test('Basic get&set&delete of Map property (handle conflict)', async function ma
   map1.set('stuff', 'c1')
   testConnector.flushAllMessages()
   for (let user of users) {
-    var u = user.get('map', Y.Map)
+    var u = user.define('map', Y.Map)
     t.assert(u.get('stuff') === undefined)
   }
   await compareUsers(t, users)
@@ -135,7 +135,7 @@ test('Basic get&set of Map property (handle three conflicts)', async function ma
   map2.set('stuff', 'c3')
   testConnector.flushAllMessages()
   for (let user of users) {
-    var u = user.get('map', Y.Map)
+    var u = user.define('map', Y.Map)
     t.compare(u.get('stuff'), 'c0')
   }
   await compareUsers(t, users)
@@ -155,7 +155,7 @@ test('Basic get&set&delete of Map property (handle three conflicts)', async func
   map3.set('stuff', 'c3')
   testConnector.flushAllMessages()
   for (let user of users) {
-    var u = user.get('map', Y.Map)
+    var u = user.define('map', Y.Map)
     t.assert(u.get('stuff') === undefined)
   }
   await compareUsers(t, users)
@@ -303,12 +303,12 @@ var mapTransactions = [
   function set (t, user, prng) {
     let key = random.oneOf(prng, ['one', 'two'])
     var value = random.utf16String(prng)
-    user.get('map', Y.Map).set(key, value)
+    user.define('map', Y.Map).set(key, value)
   },
   function setType (t, user, prng) {
     let key = random.oneOf(prng, ['one', 'two'])
     var type = random.oneOf(prng, [new Y.Array(), new Y.Map()])
-    user.get('map', Y.Map).set(key, type)
+    user.define('map', Y.Map).set(key, type)
     if (type instanceof Y.Array) {
       type.insert(0, [1, 2, 3, 4])
     } else {
@@ -317,7 +317,7 @@ var mapTransactions = [
   },
   function _delete (t, user, prng) {
     let key = random.oneOf(prng, ['one', 'two'])
-    user.get('map', Y.Map).delete(key)
+    user.define('map', Y.Map).delete(key)
   }
 ]
 
diff --git a/test/y-xml.tests.js b/test/y-xml.tests.js
index 4bccabba..6fba7470 100644
--- a/test/y-xml.tests.js
+++ b/test/y-xml.tests.js
@@ -61,20 +61,24 @@ test('attribute modifications (y -> dom)', async function xml2 (t) {
 })
 
 test('attribute modifications (dom -> y)', async function xml3 (t) {
-  var { users, xml0, dom0 } = await initArrays(t, { users: 3 })
+  var { users, xml0, dom0, domBinding0 } = await initArrays(t, { users: 3 })
   dom0.setAttribute('height', '100px')
+  domBinding0.flushDomChanges()
   t.assert(xml0.getAttribute('height') === '100px', 'setAttribute')
   dom0.removeAttribute('height')
+  domBinding0.flushDomChanges()
   t.assert(xml0.getAttribute('height') == null, 'removeAttribute')
   dom0.setAttribute('class', 'stuffy stuff')
+  domBinding0.flushDomChanges()
   t.assert(xml0.getAttribute('class') === 'stuffy stuff', 'set class attribute')
   await compareUsers(t, users)
 })
 
 test('element insert (dom -> y)', async function xml4 (t) {
-  var { users, xml0, dom0 } = await initArrays(t, { users: 3 })
+  var { users, xml0, dom0, domBinding0 } = await initArrays(t, { users: 3 })
   dom0.insertBefore(document.createTextNode('some text'), null)
   dom0.insertBefore(document.createElement('p'), null)
+  domBinding0.flushDomChanges()
   t.assert(xml0.get(0).toString() === 'some text', 'Retrieve Text Node')
   t.assert(xml0.get(1).nodeName === 'P', 'Retrieve Element node')
   await compareUsers(t, users)
@@ -90,10 +94,12 @@ test('element insert (y -> dom)', async function xml5 (t) {
 })
 
 test('y on insert, then delete (dom -> y)', async function xml6 (t) {
-  var { users, xml0, dom0 } = await initArrays(t, { users: 3 })
+  var { users, xml0, dom0, domBinding0 } = await initArrays(t, { users: 3 })
   dom0.insertBefore(document.createElement('p'), null)
+  domBinding0.flushDomChanges()
   t.assert(xml0.length === 1, 'one node present')
   dom0.childNodes[0].remove()
+  domBinding0.flushDomChanges()
   t.assert(xml0.length === 0, 'no node present after delete')
   await compareUsers(t, users)
 })
@@ -164,11 +170,13 @@ test('Receive a bunch of elements (with disconnect)', async function xml12 (t) {
 })
 
 test('move element to a different position', async function xml13 (t) {
-  var { testConnector, users, dom0, dom1 } = await initArrays(t, { users: 3 })
+  var { testConnector, users, dom0, dom1, domBinding0, domBinding1 } = await initArrays(t, { users: 3 })
   dom0.append(document.createElement('div'))
   dom0.append(document.createElement('h1'))
+  domBinding0.flushDomChanges()
   testConnector.flushAllMessages()
   dom1.insertBefore(dom1.childNodes[0], null)
+  domBinding1.flushDomChanges()
   t.assert(dom1.childNodes[0].nodeName === 'H1', 'div was deleted (user 0)')
   t.assert(dom1.childNodes[1].nodeName === 'DIV', 'div was moved to the correct position (user 0)')
   t.assert(dom1.childNodes[0].nodeName === 'H1', 'div was deleted (user 1)')
@@ -189,6 +197,7 @@ test('filter node', async function xml14 (t) {
   domBinding1.setFilter(domFilter)
   dom0.append(document.createElement('div'))
   dom0.append(document.createElement('h1'))
+  domBinding0.flushDomChanges()
   testConnector.flushAllMessages()
   t.assert(dom1.childNodes.length === 1, 'Only one node was not transmitted')
   t.assert(dom1.childNodes[0].nodeName === 'DIV', 'div node was transmitted')
@@ -206,6 +215,7 @@ test('filter attribute', async function xml15 (t) {
   dom0.setAttribute('hidden', 'true')
   dom0.setAttribute('style', 'height: 30px')
   dom0.setAttribute('data-me', '77')
+  domBinding0.flushDomChanges()
   testConnector.flushAllMessages()
   t.assert(dom0.getAttribute('hidden') === 'true', 'User 0 still has the attribute')
   t.assert(dom1.getAttribute('hidden') == null, 'User 1 did not receive update')
@@ -215,7 +225,7 @@ test('filter attribute', async function xml15 (t) {
 })
 
 test('deep element insert', async function xml16 (t) {
-  var { testConnector, users, dom0, dom1 } = await initArrays(t, { users: 3 })
+  var { testConnector, users, dom0, dom1, domBinding0 } = await initArrays(t, { users: 3 })
   let deepElement = document.createElement('p')
   let boldElement = document.createElement('b')
   let attrElement = document.createElement('img')
@@ -225,6 +235,7 @@ test('deep element insert', async function xml16 (t) {
   deepElement.append(attrElement)
   dom0.append(deepElement)
   let str0 = dom0.outerHTML
+  domBinding0.flushDomChanges()
   testConnector.flushAllMessages()
   let str1 = dom1.outerHTML
   t.compare(str0, str1, 'Dom string representation matches')
@@ -253,8 +264,8 @@ test('treeWalker', async function xml17 (t) {
  * Incoming changes that contain malicious attributes should be deleted.
  */
 test('Filtering remote changes', async function xmlFilteringRemote (t) {
-  var { testConnector, users, xml0, xml1, domBinding0 } = await initArrays(t, { users: 3 })
-  domBinding0.setFilter(function (nodeName, attributes) {
+  var { testConnector, users, xml0, xml1, domBinding0, domBinding1 } = await initArrays(t, { users: 3 })
+  const filter = (nodeName, attributes) => {
     attributes.delete('malicious')
     if (nodeName === 'HIDEME') {
       return null
@@ -263,7 +274,9 @@ test('Filtering remote changes', async function xmlFilteringRemote (t) {
     } else {
       return attributes
     }
-  })
+  }
+  domBinding0.setFilter(filter)
+  domBinding1.setFilter(filter)
   let paragraph = new Y.XmlElement('p')
   let hideMe = new Y.XmlElement('hideMe')
   let span = new Y.XmlElement('span')
@@ -275,13 +288,16 @@ test('Filtering remote changes', async function xmlFilteringRemote (t) {
   let tag2 = new Y.XmlElement('tag')
   tag2.setAttribute('isHidden', 'true')
   paragraph.insert(0, [tag2])
+  domBinding0.flushDomChanges()
   testConnector.flushAllMessages()
   // check dom
   domBinding0.typeToDom.get(paragraph).setAttribute('malicious', 'true')
   domBinding0.typeToDom.get(span).setAttribute('malicious', 'true')
+  domBinding0.flushDomChanges()
   // check incoming attributes
   xml1.get(0).get(0).setAttribute('malicious', 'true')
   xml1.insert(0, [new Y.XmlElement('hideMe')])
+  domBinding0.flushDomChanges()
   testConnector.flushAllMessages()
 
   await compareUsers(t, users)
@@ -292,30 +308,36 @@ var xmlTransactions = [
   function attributeChange (t, user, prng) {
     // random.word generates non-empty words. prepend something
     user.dom.setAttribute('_' + random.word(prng), random.word(prng))
+    user.domBinding.flushDomChanges()
   },
   function attributeChangeHidden (t, user, prng) {
     user.dom.setAttribute('hidden', random.word(prng))
+    user.domBinding.flushDomChanges()
   },
   function insertText (t, user, prng) {
     let dom = user.dom
     var succ = dom.children.length > 0 ? random.oneOf(prng, dom.children) : null
     dom.insertBefore(document.createTextNode(random.word(prng)), succ)
+    user.domBinding.flushDomChanges()
   },
   function insertHiddenDom (t, user, prng) {
     let dom = user.dom
     var succ = dom.children.length > 0 ? random.oneOf(prng, dom.children) : null
     dom.insertBefore(document.createElement('hidden'), succ)
+    user.domBinding.flushDomChanges()
   },
   function insertDom (t, user, prng) {
     let dom = user.dom
     var succ = dom.children.length > 0 ? random.oneOf(prng, dom.children) : null
     dom.insertBefore(document.createElement('my-' + random.word(prng)), succ)
+    user.domBinding.flushDomChanges()
   },
   function deleteChild (t, user, prng) {
     let dom = user.dom
     if (dom.childNodes.length > 0) {
       var d = random.oneOf(prng, dom.childNodes)
       d.remove()
+      user.domBinding.flushDomChanges()
     }
   },
   function insertTextSecondLayer (t, user, prng) {
@@ -324,6 +346,7 @@ var xmlTransactions = [
       let dom2 = random.oneOf(prng, dom.children)
       let succ = dom2.childNodes.length > 0 ? random.oneOf(prng, dom2.childNodes) : null
       dom2.insertBefore(document.createTextNode(random.word(prng)), succ)
+      user.domBinding.flushDomChanges()
     }
   },
   function insertDomSecondLayer (t, user, prng) {
@@ -332,6 +355,7 @@ var xmlTransactions = [
       let dom2 = random.oneOf(prng, dom.children)
       let succ = dom2.childNodes.length > 0 ? random.oneOf(prng, dom2.childNodes) : null
       dom2.insertBefore(document.createElement('my-' + random.word(prng)), succ)
+      user.domBinding.flushDomChanges()
     }
   },
   function deleteChildSecondLayer (t, user, prng) {
@@ -342,6 +366,7 @@ var xmlTransactions = [
         let d = random.oneOf(prng, dom2.childNodes)
         d.remove()
       }
+      user.domBinding.flushDomChanges()
     }
   }
 ]
diff --git a/tests-lib/helper.js b/tests-lib/helper.js
index 35738540..ad28d4dc 100644
--- a/tests-lib/helper.js
+++ b/tests-lib/helper.js
@@ -6,10 +6,12 @@ import { defragmentItemContent } from '../src/Util/defragmentItemContent.js'
 import Quill from 'quill'
 import GC from '../src/Struct/GC.js'
 import * as random from '../lib/random/random.js'
-import * as message from '../src/message.js'
+import * as syncProtocol from '../src/protocols/syncProtocol.js'
 import * as encoding from '../lib/encoding.js'
 import * as decoding from '../lib/decoding.js'
 import { createMutex } from '../lib/mutex.js'
+import QuillBinding from '../bindings/QuillBinding/QuillBinding.js'
+import DomBinding from '../bindings/DomBinding/DomBinding.js'
 
 export * from '../src/index.js'
 
@@ -21,7 +23,7 @@ const afterTransaction = (y, transaction) => {
   y.mMux(() => {
     if (transaction.encodedStructsLen > 0) {
       const encoder = encoding.createEncoder()
-      message.writeUpdate(encoder, transaction.encodedStructsLen, transaction.encodedStructs)
+      syncProtocol.writeUpdate(encoder, transaction.encodedStructsLen, transaction.encodedStructs)
       broadcastMessage(y, encoding.toBuffer(encoder))
     }
   })
@@ -31,8 +33,9 @@ export class TestYInstance extends Y.Y {
   /**
    * @param {TestConnector} testConnector
    */
-  constructor (testConnector) {
+  constructor (testConnector, clientID) {
     super()
+    this.userID = clientID // overwriting clientID
     /**
      * @type {TestConnector}
      */
@@ -64,17 +67,19 @@ export class TestYInstance extends Y.Y {
    */
   connect () {
     if (!this.tc.onlineConns.has(this)) {
+      this.tc.onlineConns.add(this)
       const encoder = encoding.createEncoder()
-      message.writeSyncStep1(encoder, this)
+      syncProtocol.writeSyncStep1(encoder, this)
       // publish SyncStep1
       broadcastMessage(this, encoding.toBuffer(encoder))
       this.tc.onlineConns.forEach(remoteYInstance => {
-        // remote instance sends instance to this instance
-        const encoder = encoding.createEncoder()
-        message.writeSyncStep1(encoder, remoteYInstance)
-        this._receive(encoding.toBuffer(encoder), remoteYInstance)
+        if (remoteYInstance !== this) {
+          // remote instance sends instance to this instance
+          const encoder = encoding.createEncoder()
+          syncProtocol.writeSyncStep1(encoder, remoteYInstance)
+          this._receive(encoding.toBuffer(encoder), remoteYInstance)
+        }
       })
-      this.tc.onlineConns.add(this)
     }
   }
   /**
@@ -117,9 +122,10 @@ export class TestConnector {
   }
   /**
    * Create a new Y instance and add it to the list of connections
+   * @param {number} clientID
    */
-  createY () {
-    return new TestYInstance(this)
+  createY (clientID) {
+    return new TestYInstance(this, clientID)
   }
   /**
    * Choose random connection and flush a random message from a random sender.
@@ -139,8 +145,9 @@ export class TestConnector {
       }
       const encoder = encoding.createEncoder()
       receiver.mMux(() => {
+        console.log('receive (' + sender.userID + '->' + receiver.userID + '):\n', syncProtocol.stringifySyncMessage(decoding.createDecoder(m), receiver))
         // do not publish data created when this function is executed (could be ss2 or update message)
-        message.readMessage(decoding.createDecoder(m), encoder, receiver)
+        syncProtocol.readSyncMessage(decoding.createDecoder(m), encoder, receiver)
       })
       if (encoding.length(encoder) > 0) {
         // send reply message
@@ -202,12 +209,15 @@ export class TestConnector {
  * @param {TestYInstance} y // publish message created by `y` to all other online clients
  * @param {ArrayBuffer} m
  */
-const broadcastMessage = (y, m) =>
-  y.tc.onlineConns.forEach(remoteYInstance => {
-    if (remoteYInstance !== y) {
-      remoteYInstance._receive(m, y)
-    }
-  })
+const broadcastMessage = (y, m) => {
+  if (y.tc.onlineConns.has(y)) {
+    y.tc.onlineConns.forEach(remoteYInstance => {
+      if (remoteYInstance !== y) {
+        remoteYInstance._receive(m, y)
+      }
+    })
+  }
+}
 
 /**
  * Convert DS to a proper DeleteSet of Map.
@@ -295,7 +305,7 @@ export function compareUsers (t, users) {
     data.os = ops
     data.ds = getDeleteSet(u)
     const ss = {}
-    u.ss.state.forEach((user, clock) => {
+    u.ss.state.forEach((clock, user) => {
       ss[user] = clock
     })
     data.ss = ss
@@ -347,20 +357,20 @@ export function initArrays (t, opts) {
   const testConnector = new TestConnector(prng)
   result.testConnector = testConnector
   for (let i = 0; i < opts.users; i++) {
-    let y = testConnector.createY()
+    let y = testConnector.createY(i)
     result.users.push(y)
     result['array' + i] = y.define('array', Y.Array)
     result['map' + i] = y.define('map', Y.Map)
     const yxml = y.define('xml', Y.XmlElement)
     result['xml' + i] = yxml
     const dom = document.createElement('my-dom')
-    const domBinding = new Y.DomBinding(yxml, dom, { filter })
+    const domBinding = new DomBinding(yxml, dom, { filter })
     result['domBinding' + i] = domBinding
     result['dom' + i] = dom
     const textType = y.define('text', Y.Text)
     result['text' + i] = textType
     const quill = new Quill(document.createElement('div'))
-    result['quillBinding' + i] = new Y.QuillBinding(textType, quill)
+    result['quillBinding' + i] = new QuillBinding(textType, quill)
     result['quill' + i] = quill
     y.quill = quill // put quill on the y object (so we can use it later)
     y.dom = dom