diff --git a/tests/signing.sh b/tests/signing.sh
index 46929639..9e29e3fb 100644
--- a/tests/signing.sh
+++ b/tests/signing.sh
@@ -62,6 +62,10 @@ outPathCA=$(IMPURE_VAR1=foo IMPURE_VAR2=bar nix-build ./fixed.nix -A good.0 --no
 nix verify $outPathCA
 nix verify $outPathCA --sigs-needed 1000
 
+# Check that signing a content-addressed path doesn't overflow validSigs
+nix sign-paths --key-file $TEST_ROOT/sk1 $outPathCA
+nix verify -r $outPathCA --sigs-needed 1000 --trusted-public-keys $pk1
+
 # Copy to a binary cache.
 nix copy --to file://$cacheDir $outPath2