diff --git a/commonspace/headsync/diffsyncer_test.go b/commonspace/headsync/diffsyncer_test.go
index 4c6fcdc9..b49c2178 100644
--- a/commonspace/headsync/diffsyncer_test.go
+++ b/commonspace/headsync/diffsyncer_test.go
@@ -1,7 +1,14 @@
 package headsync
 
 import (
+	"bytes"
 	"context"
+	"fmt"
+	"github.com/anyproto/any-sync/app/ldiff"
+	"github.com/anyproto/any-sync/commonspace/object/acl/aclrecordproto"
+	"github.com/anyproto/any-sync/commonspace/object/acl/liststorage/mock_liststorage"
+	"github.com/anyproto/any-sync/commonspace/object/tree/treechangeproto"
+	"github.com/anyproto/any-sync/commonspace/object/tree/treestorage/mock_treestorage"
 	"github.com/anyproto/any-sync/commonspace/spacesyncproto"
 	"github.com/anyproto/any-sync/net/peer"
 	"github.com/golang/mock/gomock"
@@ -11,6 +18,42 @@ import (
 	"time"
 )
 
+type pushSpaceRequestMatcher struct {
+	spaceId     string
+	aclRootId   string
+	settingsId  string
+	credential  []byte
+	spaceHeader *spacesyncproto.RawSpaceHeaderWithId
+}
+
+func newPushSpaceRequestMatcher(
+	spaceId string,
+	aclRootId string,
+	settingsId string,
+	credential []byte,
+	spaceHeader *spacesyncproto.RawSpaceHeaderWithId) *pushSpaceRequestMatcher {
+	return &pushSpaceRequestMatcher{
+		spaceId:     spaceId,
+		aclRootId:   aclRootId,
+		settingsId:  settingsId,
+		credential:  credential,
+		spaceHeader: spaceHeader,
+	}
+}
+
+func (p pushSpaceRequestMatcher) Matches(x interface{}) bool {
+	res, ok := x.(*spacesyncproto.SpacePushRequest)
+	if !ok {
+		return false
+	}
+
+	return res.Payload.AclPayloadId == p.aclRootId && res.Payload.SpaceHeader == p.spaceHeader && res.Payload.SpaceSettingsPayloadId == p.settingsId && bytes.Equal(p.credential, res.Credential)
+}
+
+func (p pushSpaceRequestMatcher) String() string {
+	return ""
+}
+
 type mockPeer struct {
 }
 
@@ -58,12 +101,12 @@ func (fx *headSyncFixture) initDiffSyncer(t *testing.T) {
 }
 
 func TestDiffSyncer(t *testing.T) {
-	fx := newHeadSyncFixture(t)
-	fx.initDiffSyncer(t)
-	defer fx.stop()
 	ctx := context.Background()
 
 	t.Run("diff syncer sync", func(t *testing.T) {
+		fx := newHeadSyncFixture(t)
+		fx.initDiffSyncer(t)
+		defer fx.stop()
 		mPeer := mockPeer{}
 		fx.peerManagerMock.EXPECT().
 			GetResponsiblePeers(gomock.Any()).
@@ -77,6 +120,122 @@ func TestDiffSyncer(t *testing.T) {
 		fx.treeSyncerMock.EXPECT().SyncAll(gomock.Any(), mPeer.Id(), []string{"changed"}, []string{"new"}).Return(nil)
 		require.NoError(t, fx.diffSyncer.Sync(ctx))
 	})
+
+	t.Run("diff syncer sync conf error", func(t *testing.T) {
+		fx := newHeadSyncFixture(t)
+		fx.initDiffSyncer(t)
+		defer fx.stop()
+		ctx := context.Background()
+		fx.peerManagerMock.EXPECT().
+			GetResponsiblePeers(gomock.Any()).
+			Return(nil, fmt.Errorf("some error"))
+
+		require.Error(t, fx.diffSyncer.Sync(ctx))
+	})
+
+	t.Run("deletion state remove objects", func(t *testing.T) {
+		fx := newHeadSyncFixture(t)
+		fx.initDiffSyncer(t)
+		defer fx.stop()
+		deletedId := "id"
+		fx.deletionStateMock.EXPECT().Exists(deletedId).Return(true)
+
+		// this should not result in any mock being called
+		fx.diffSyncer.UpdateHeads(deletedId, []string{"someHead"})
+	})
+
+	t.Run("update heads updates diff", func(t *testing.T) {
+		fx := newHeadSyncFixture(t)
+		fx.initDiffSyncer(t)
+		defer fx.stop()
+		newId := "newId"
+		newHeads := []string{"h1", "h2"}
+		hash := "hash"
+		fx.diffMock.EXPECT().Set(ldiff.Element{
+			Id:   newId,
+			Head: concatStrings(newHeads),
+		})
+		fx.diffMock.EXPECT().Hash().Return(hash)
+		fx.deletionStateMock.EXPECT().Exists(newId).Return(false)
+		fx.storageMock.EXPECT().WriteSpaceHash(hash)
+		fx.diffSyncer.UpdateHeads(newId, newHeads)
+	})
+
+	t.Run("diff syncer sync space missing", func(t *testing.T) {
+		fx := newHeadSyncFixture(t)
+		fx.initDiffSyncer(t)
+		defer fx.stop()
+		aclStorageMock := mock_liststorage.NewMockListStorage(fx.ctrl)
+		settingsStorage := mock_treestorage.NewMockTreeStorage(fx.ctrl)
+		settingsId := "settingsId"
+		aclRootId := "aclRootId"
+		aclRoot := &aclrecordproto.RawAclRecordWithId{
+			Id: aclRootId,
+		}
+		settingsRoot := &treechangeproto.RawTreeChangeWithId{
+			Id: settingsId,
+		}
+		spaceHeader := &spacesyncproto.RawSpaceHeaderWithId{}
+		spaceSettingsId := "spaceSettingsId"
+		credential := []byte("credential")
+
+		fx.peerManagerMock.EXPECT().
+			GetResponsiblePeers(gomock.Any()).
+			Return([]peer.Peer{mockPeer{}}, nil)
+		fx.diffMock.EXPECT().
+			Diff(gomock.Any(), gomock.Eq(NewRemoteDiff(fx.spaceState.SpaceId, fx.clientMock))).
+			Return(nil, nil, nil, spacesyncproto.ErrSpaceMissing)
+
+		fx.storageMock.EXPECT().AclStorage().Return(aclStorageMock, nil)
+		fx.storageMock.EXPECT().SpaceHeader().Return(spaceHeader, nil)
+		fx.storageMock.EXPECT().SpaceSettingsId().Return(spaceSettingsId)
+		fx.storageMock.EXPECT().TreeStorage(spaceSettingsId).Return(settingsStorage, nil)
+
+		settingsStorage.EXPECT().Root().Return(settingsRoot, nil)
+		aclStorageMock.EXPECT().
+			Root().
+			Return(aclRoot, nil)
+		fx.credentialProviderMock.EXPECT().
+			GetCredential(gomock.Any(), spaceHeader).
+			Return(credential, nil)
+		fx.clientMock.EXPECT().
+			SpacePush(gomock.Any(), newPushSpaceRequestMatcher(fx.spaceState.SpaceId, aclRootId, settingsId, credential, spaceHeader)).
+			Return(nil, nil)
+		fx.peerManagerMock.EXPECT().SendPeer(gomock.Any(), "peerId", gomock.Any())
+
+		require.NoError(t, fx.diffSyncer.Sync(ctx))
+	})
+
+	t.Run("diff syncer sync unexpected", func(t *testing.T) {
+		fx := newHeadSyncFixture(t)
+		fx.initDiffSyncer(t)
+		defer fx.stop()
+		fx.peerManagerMock.EXPECT().
+			GetResponsiblePeers(gomock.Any()).
+			Return([]peer.Peer{mockPeer{}}, nil)
+		fx.diffMock.EXPECT().
+			Diff(gomock.Any(), gomock.Eq(NewRemoteDiff(fx.spaceState.SpaceId, fx.clientMock))).
+			Return(nil, nil, nil, spacesyncproto.ErrUnexpected)
+
+		require.NoError(t, fx.diffSyncer.Sync(ctx))
+	})
+
+	t.Run("diff syncer sync space is deleted error", func(t *testing.T) {
+		fx := newHeadSyncFixture(t)
+		fx.initDiffSyncer(t)
+		defer fx.stop()
+		mPeer := mockPeer{}
+		fx.peerManagerMock.EXPECT().
+			GetResponsiblePeers(gomock.Any()).
+			Return([]peer.Peer{mPeer}, nil)
+		fx.diffMock.EXPECT().
+			Diff(gomock.Any(), gomock.Eq(NewRemoteDiff(fx.spaceState.SpaceId, fx.clientMock))).
+			Return(nil, nil, nil, spacesyncproto.ErrSpaceIsDeleted)
+		fx.storageMock.EXPECT().SpaceSettingsId().Return("settingsId")
+		fx.treeSyncerMock.EXPECT().SyncAll(gomock.Any(), mPeer.Id(), []string{"settingsId"}, nil).Return(nil)
+
+		require.NoError(t, fx.diffSyncer.Sync(ctx))
+	})
 }
 
 //