.

wcfs/wcfs_test.py

@@ -1303,6 +1303,7 @@ def test_wcfs():
 
     # 5(f) is kept unaccessed to test how wcfs.go handles δFtail rebuild after
     # it sees not yet accessed ZBlk that has change history.
+    assert f.cached()[5] == 0
 #   f.assertBlk(5, 'f4', {wl3: {5:at0},         wl3_: {5:at0},         wl2: {5:at0}}) # XXX at0->ø?
 #   w_assertPin(               {2:at3, 5:at0},        {2:at3, 5:at0},       {2:at2, 5:at0})
 
@@ -1332,21 +1333,23 @@ def test_wcfs():
     f.assertBlk(1, '',   {wl3: {},                      wl3_: {}})
     w_assertPin(               {2:at3, 6:at0})
 
-    f.assertBlk(2, 'c5', {wl3: {},                      wl3_: {}})  # blk2 already pinned on wl3
+    f.assertBlk(2, 'c5', {wl3: {},                      wl3_: {}})  # 2(c) already pinned on wl3
     w_assertPin(               {2:at3, 6:at0})
 
-    f.assertBlk(3, 'd5', {wl3: {3:at2},                 wl3_: {}})  # wl3_ not notified
+    f.assertBlk(3, 'd5', {wl3: {3:at2},                 wl3_: {}})  # 3(d) was not pinned on wl3; wl3_ not notified
     w_assertPin(               {2:at3, 3:at2, 6:at0})
 
     f.assertBlk(4, '',   {wl3: {},                      wl3_: {}})
     w_assertPin(               {2:at3, 3:at2, 6:at0})
 
-    # 5(f) is kept still unaccessed
+    # 5(f) is kept still unaccessed, so that when it will be accessed
+    # corresponding ZBlk will have change history with len > 1.
+    assert f.cached()[5] == 0
 #   f.assertBlk(5, 'f4', {wl3: {},                      wl3_: {}})
 #   w_assertPin(               {2:at3, 3:at2, 5:at0})
 
-    f.assertBlk(6, 'g4', {wl3: {6:at0},                 wl3_: {}})
-    w_assertPin(               {2:at3, 6:at0})
+    f.assertBlk(6, 'g4', {wl3: {},                      wl3_: {}})
+    w_assertPin(               {2:at3, 3:at2, 6:at0})
 
     return