.

wcfs/internal/xbtree/δbtail_test.go

@@ -36,7 +36,7 @@ package xbtree
 //   b) transition a BTree in ZODB through random tree topologies and feed
 //      ΔBtail through created database transactions.
 //
-// TestΔBTail and TestΔBTailAllStructs implement approaches "a" and "b" correspondingly.
+// TestΔBTail and TestΔBTailRandom implement approaches "a" and "b" correspondingly.
 //
 // testprog/treegen.py is used as helper to both:	XXX moved to xbtreetest
 //
@@ -1353,8 +1353,8 @@ func TestΔBTail(t *testing.T) {
 
 }
 
-// TestΔBTailAllStructs verifies ΔBtail on tree topologies generated by AllStructs.
-func TestΔBTailAllStructs(t *testing.T) {
+// TestΔBTailRandom verifies ΔBtail on random tree topologies generated by AllStructs.
+func TestΔBTailRandom(t *testing.T) {
 	X := exc.Raiseif
 
 	// considerations:

wcfs/internal/zdata/δftail.go

@@ -79,6 +79,7 @@ type ΔFtail struct {
 
 	trackSetZFile setOid                  // set of tracked ZBigFiles	as of @head
 	trackSetZBlk  map[zodb.Oid]*zblkTrack // zblk -> {} root -> {}blk	as of @head
+
 // XXX kill
 ///*
 	// XXX don't need vδF - everything is reconstructed at runtime from .δBtail.vδT
@@ -249,7 +250,6 @@ func (δFtail *ΔFtail) Update(δZ *zodb.EventCommit) (_ ΔF, err error) {
 				δF.ByFile[file] = δfile
 			}
 			for blk /*, zblk*/ := range δt {
-				// FIXME stub - need to take both keys and zblk changes into account
 				// XXX document, and in particular how to include atTail
 				δfile.Blocks.Add(blk)
 			}

wcfs/internal/zdata/δftail_test.go

@@ -20,10 +20,26 @@
 package zdata
 // tests for δftail.go
 //
-// This are the main tests for ΔFtail functionality.
-// XXX overview
-// XXX we assume that ΔBtail works correctly (this is covered by ΔBtail tests)
-// XXX -> no need to exercise many different topologies and tracking sets.
+// This are the main tests for ΔFtail functionality. The primary testing
+// concern is to verify how ΔFtail merges ΔBtail and ΔZtail histories on Update
+// and queries.
+//
+// We assume that ΔBtail works correctly (this is covered by ΔBtail tests)
+// -> no need to exercise many different topologies and tracking sets.
+//
+// Since ΔFtail does not recompute anything by itself when tracking set
+// changes, and only merges δBtail and δZtail histories on queries, there is no
+// need to exercise many different tracking sets. Once again we assume that
+// ΔBtail works correctly and verify δFtail only with track=[-∞,∞).
+//
+// There are 2 testing approaches:
+//
+//   a) transition a ZBigFile in ZODB through particular .blktab and ZBlk
+//      states and feed ΔFtail through created database transactions.
+//   b) transition a ZBigFile in ZODB through random     .blktab and ZBlk
+//      states and feed ΔFtail through created database transactions.
+//
+// TestΔFtail and TestΔFtail implement approaches "a" and "b" correspondingly.
 
 import (
 	"context"