diff --git a/tests/test-rhg-no-generaldelta.t b/tests/test-rhg-no-generaldelta.t
new file mode 100644
--- /dev/null
+++ b/tests/test-rhg-no-generaldelta.t
@@ -0,0 +1,30 @@
+
+  $ NO_FALLBACK="env RHG_ON_UNSUPPORTED=abort"
+
+  $ cat << EOF >> $HGRCPATH
+  > [format]
+  > sparse-revlog = no
+  > EOF
+
+  $ hg init repo --config format.generaldelta=no --config format.usegeneraldelta=no
+  $ cd repo
+  $ seq.py 50 > f
+  $ hg commit -q -Am initial
+  $ echo x >> f
+  $ hg commit -q -Am x
+  $ hg update ".^"
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ (seq.py 50; echo x) | (read; cat) > f
+  $ hg commit -q -Am y
+  $ hg debugdeltachain f
+      rev  chain# chainlen     prev   delta       size    rawsize  chainsize     ratio   lindist extradist extraratio
+        0       1        1       -1    base         79        141         79   0.56028        79         0    0.00000
+        1       1        2        0    prev         14        143         93   0.65035        93         0    0.00000
+        2       1        3        1    prev         12        141        105   0.74468       105         0    0.00000
+
+rhg breaks on non-generaldelta revlogs:
+
+  $ $NO_FALLBACK hg cat f -r . | f --sha256 --size
+  abort: corrupted revlog (rhg !)
+  size=0, sha256=e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 (rhg !)
+  size=141, sha256=1a7fe778e33d64d5e14a9a126b77038b328356e67bacf308797bc0e39bf204f3 (no-rhg !)