.

wcfs/internal/xbtree/1.patch

+tTreeEnv += Run to run subtest
+
+Canceled becase too much change for sole single use-case.
+Probably drop this patch.
+diff --git a/wcfs/internal/xbtree/δbtail_test.go b/wcfs/internal/xbtree/δbtail_test.go
+index c810941a..ed8020be 100644
+--- a/wcfs/internal/xbtree/δbtail_test.go
++++ b/wcfs/internal/xbtree/δbtail_test.go
+@@ -905,7 +905,7 @@ func xverifyΔBTail_Update1(t *testing.T, subj string, db *zodb.DB, treeRoot zod
+ // assertTrack verifies that trackSet == trackSetOK.
+ // XXX place
+ // XXX inline into δbtail.assertTrack?
+-func _assertTrack(t *testing.T, subj string, trackSet, trackSetOK PPTreeSubSet) {
++func _assertTrack(t testing.TB, subj string, trackSet, trackSetOK PPTreeSubSet) {
+ 	t.Helper()
+ 	if !trackSet.Equal(trackSetOK) {
+ 		t.Errorf("%s:\n\thave: %v\n\twant: %v", subj, trackSet, trackSetOK)
+@@ -915,7 +915,7 @@ func _assertTrack(t *testing.T, subj string, trackSet, trackSetOK PPTreeSubSet)
+ // assertTrack verifies state of .trackSet and ΔTtail.trackNew.
+ // it assumes that only one tree root is being tracked.
+ // XXX place
+-func (δBtail *ΔBtail) assertTrack(t *testing.T, subj string, trackSetOK PPTreeSubSet, trackNewOK PPTreeSubSet) {
++func (δBtail *ΔBtail) assertTrack(t testing.TB, subj string, trackSetOK PPTreeSubSet, trackNewOK PPTreeSubSet) {
+ 	t.Helper()
+ 	_assertTrack(t, subj + ": trackSet", δBtail.trackSet, trackSetOK)
+ 
+@@ -954,11 +954,17 @@ func (δBtail *ΔBtail) assertTrack(t *testing.T, subj string, trackSetOK PPTree
+ 
+ // xverifyΔBTail_rebuild verifies ΔBtail.rebuild during t0->t1->t2 transition.
+ //
++// t0,t1,t2 are taken as t.Head~~,t.Head~,t.Head
++//
+ // t0->t1 exercises from-scratch rebuild,
+ // t1->t2 further exercises incremental rebuild.
+ //
+ // It also exercises rebuild phase of ΔBtail.Update.
+-func xverifyΔBTail_rebuild(t *testing.T, db *zodb.DB, treeRoot zodb.Oid, t0, t1, t2 *tTreeCommit) {
++func xverifyΔBTail_rebuild(t tTreeEnv) {
++	t2 := t.Head()
++	t1 := t2.prev
++	t0 := t1.prev
++
+ 	t.Run(fmt.Sprintf("rebuild/%s→%s", t0.tree, t1.tree), func(t *testing.T) {
+ 		tAllKeys := allTestKeys(t0, t1, t2)
+ 		tAllKeyv := tAllKeys.SortedElements()
+@@ -1001,12 +1007,12 @@ func xverifyΔBTail_rebuild(t *testing.T, db *zodb.DB, treeRoot zodb.Oid, t0, t1
+ 				}
+ 			}
+ 
+-			t.Run(fmt.Sprintf(" T%s;R", keys1), func(t *testing.T) {
+-				δbtail := NewΔBtail(t0.at, db)
++			t.Run(fmt.Sprintf(" T%s;R", keys1), func(t tTreeEnv) {
++				δbtail := NewΔBtail(t0.at, t.DB())
+ 
+ 				// assert trackSet=ø, trackNew=ø, vδB=[]
+ 				δbtail.assertTrack(t, "@at0", ø, ø)
+-				assertΔTtail(t, "@at0", δbtail, t0, treeRoot, xat,
++				assertΔTtail(t, "@at0", δbtail, xat,
+ 					/*vδT=ø*/)
+ 
+ 				xverifyΔBTail_rebuild_U(t, δbtail, treeRoot, t0, t1, xat,
+@@ -1120,10 +1126,10 @@ func xverifyΔBTail_rebuild(t *testing.T, db *zodb.DB, treeRoot zodb.Oid, t0, t1
+ 								/* trackSet=*/ t2.xkv.trackSet(keys12R2),
+ 								/*vδT=*/ δkv1_k12R2, δkv2_k12R2)
+ 
+-							// XXX move vvv to separate test (out of this inner loop)
+-							// ΔBtail.Clone had bug that aliased klon data to orig
+-							assertΔTtail(t, "BUG: after clone check", δbtail, t2, treeRoot, xat,
+-								/*vδT=*/ δkv1_k1R2, δkv2_k1R2)
++//							// XXX move vvv to separate test (out of this inner loop)
++//							// ΔBtail.Clone had bug that aliased klon data to orig
++//							assertΔTtail(t, "BUG: after clone check", δbtail, t2, treeRoot, xat,
++//								/*vδT=*/ δkv1_k1R2, δkv2_k1R2)
+ 						//})
+ 					}
+ 				})
+@@ -1143,7 +1149,7 @@ func xverifyΔBTail_rebuild_U(t *testing.T, δbtail *ΔBtail, treeRoot zodb.Oid,
+ 	// Update ati -> atj
+ 	δB, err := δbtail.Update(tj.δZ);  X(err)
+ 	δbtail.assertTrack(t, subj, trackSet, ø)
+-	assertΔTtail(t, subj, δbtail, tj, treeRoot, xat, vδTok...)
++	assertΔTtail(t, subj, δbtail, xat, vδTok...)
+ 
+ 	// assert δB = vδTok[-1]
+ 	var δT, δTok map[Key]Δstring
+@@ -1196,14 +1202,16 @@ func xverifyΔBTail_rebuild_TR(t *testing.T, δbtail *ΔBtail, tj *tTreeCommit,
+ 	// XXX verify Get -> XXX assertΔTtail ?
+ 
+ 	// verify δbtail.vδTbyRoot[treeRoot]
+-	assertΔTtail(t, subj, δbtail, tj, treeRoot, xat, vδTok...)
++	assertΔTtail(t, subj, δbtail, xat, vδTok...)
+ }
+ 
+ // assertΔTtail verifies state of ΔTtail that corresponds to treeRoot in δbtail.
+-func assertΔTtail(t *testing.T, subj string, δbtail *ΔBtail, tj *tTreeCommit, treeRoot zodb.Oid, xat map[zodb.Tid]string, vδTok ...map[Key]Δstring) {
++func assertΔTtail(t tTreeEnv, subj string, δbtail *ΔBtail, xat map[zodb.Tid]string, vδTok ...map[Key]Δstring) {
+ 	t.Helper()
+ 	// XXX +KVAtTail, +lastRevOf
+ 
++	tj := t.Head() // XXX just used head?
++
+ 	l := len(vδTok)
+ 	var vatOK  []zodb.Tid
+ 	var vδTok_ []map[Key]Δstring
+@@ -1219,7 +1227,7 @@ func assertΔTtail(t *testing.T, subj string, δbtail *ΔBtail, tj *tTreeCommit,
+ 		at2t[t0.at] = t0
+ 	}
+ 	vδTok = vδTok_
+-	δTtail, ok := δbtail.vδTbyRoot[treeRoot]
++	δTtail, ok := δbtail.vδTbyRoot[t.Root()]
+ 	var vδToid []ΔTree
+ 	if ok {
+ 		vδToid = δTtail.vδT
+@@ -1391,12 +1399,27 @@ func ΔBTest(xtest interface{}) ΔBTestEntry {
+ }
+ 
+ 
++// tTreeEnv is tree-based testing environment.
++//
++// It provides client side read-only access to ZODB with committed trees.
++type tTreeEnv interface {
++	Root() zodb.Oid     // oid of root node
++	Head() *tTreeCommit // most-recently committed tree
++	DB()   *zodb.DB     // DB that provides access to ZODB storage
++
++	// Run runs a subtest similarly to testing.T.Run
++	Run(name string, f func(t tTreeEnv)) bool
++
++	testing.TB
++}
++
++
+ // tTreeEnv is tree-based testing environment.
+ //
+ // It combines TreeSrv and client side access to ZODB with committed trees. XXX
+ //
+-// Create it with tTreeEnv().
+-type tTreeEnv struct {
++// Create it with tNewTreeEnv().
++type tTreeEnvMain struct {
+ 	*testing.T
+ 
+ 	work    string   // working directory
+@@ -1638,7 +1661,7 @@ func testΔBTail(t_ *testing.T, testq chan ΔBTestEntry) {
+ 
+ 		// ΔBTail.rebuild
+ 		if t0 != nil {
+-			xverifyΔBTail_rebuild(t.T, t.db, t.treeSrv.treeRoot, t0,t1,t2)
++			xverifyΔBTail_rebuild(t)
+ 		}
+ 
+ 		t0, t1 = t1, t2