--- a/tests/artifacts/scripts/generate-churning-bundle.py	Wed Dec 04 10:21:23 2024 +0100
+++ b/tests/artifacts/scripts/generate-churning-bundle.py	Tue Dec 03 23:49:37 2024 +0100
@@ -117,7 +117,7 @@
                 print("generating commit #%d/%d" % (idx, NB_CHANGESET))
             if (idx % PERIOD_BRANCHING) == 0:
                 move_back = MOVE_BACK_MIN + (idx % MOVE_BACK_RANGE)
-                hg('update', ".~%d" % move_back)
+                hg('update', "max(0+.~%d)" % move_back)
             if (idx % PERIOD_MERGING) == 0:
                 hg('merge', 'min(head())')
             updatefile(FILENAME, idx)

--- a/tests/test-sparse-revlog.t	Wed Dec 04 10:21:23 2024 +0100
+++ b/tests/test-sparse-revlog.t	Tue Dec 03 23:49:37 2024 +0100
@@ -57,6 +57,113 @@
   updated to "d9032adc8114: commit #5000"
   89 other heads for branch "default"
 
+Sanity check the graph shape
+
+  $ hg log -T '{rev} {p1rev} {p2rev}\n' --rev '0:100'
+  0 -1 -1
+  1 0 -1
+  2 1 -1
+  3 2 -1
+  4 3 -1
+  5 4 -1
+  6 5 -1
+  7 1 -1
+  8 7 6
+  9 8 -1
+  10 9 -1
+  11 10 -1
+  12 11 -1
+  13 12 -1
+  14 1 -1
+  15 14 -1
+  16 15 13
+  17 16 -1
+  18 17 -1
+  19 18 -1
+  20 19 -1
+  21 16 -1
+  22 21 -1
+  23 22 -1
+  24 23 20
+  25 24 -1
+  26 25 -1
+  27 26 -1
+  28 21 -1
+  29 28 -1
+  30 29 -1
+  31 30 -1
+  32 31 27
+  33 32 -1
+  34 33 -1
+  35 31 -1
+  36 35 -1
+  37 36 -1
+  38 37 -1
+  39 38 -1
+  40 39 34
+  41 40 -1
+  42 36 -1
+  43 42 -1
+  44 43 -1
+  45 44 -1
+  46 45 -1
+  47 46 -1
+  48 47 41
+  49 36 -1
+  50 49 -1
+  51 50 -1
+  52 51 -1
+  53 52 -1
+  54 53 -1
+  55 54 -1
+  56 51 48
+  57 56 -1
+  58 57 -1
+  59 58 -1
+  60 59 -1
+  61 60 -1
+  62 61 -1
+  63 56 -1
+  64 63 55
+  65 64 -1
+  66 65 -1
+  67 66 -1
+  68 67 -1
+  69 68 -1
+  70 66 -1
+  71 70 -1
+  72 71 62
+  73 72 -1
+  74 73 -1
+  75 74 -1
+  76 75 -1
+  77 71 -1
+  78 77 -1
+  79 78 -1
+  80 79 69
+  81 80 -1
+  82 81 -1
+  83 82 -1
+  84 71 -1
+  85 84 -1
+  86 85 -1
+  87 86 -1
+  88 87 76
+  89 88 -1
+  90 89 -1
+  91 86 -1
+  92 91 -1
+  93 92 -1
+  94 93 -1
+  95 94 -1
+  96 95 83
+  97 96 -1
+  98 91 -1
+  99 98 -1
+  100 99 -1
+
+sanity check the change pattern
+
   $ hg log --stat -r 0:3
   changeset:   0:9706f5af64f4
   user:        test