diff --git a/script/test b/script/test
index 2c6c50e5..bb29adca 100755
--- a/script/test
+++ b/script/test
@@ -6,7 +6,7 @@ function usage {
   cat <<-EOF
 USAGE
 
-  $0  [-dgGhv] [-f focus-string]
+  $0  [-dgGhv] [-f focus-string] [-s seed]
 
 OPTIONS
 
@@ -22,6 +22,10 @@ OPTIONS
 
   -f  run only tests whose description contain the given string
 
+  -s  set the seed used to control random behavior
+
+  -z  pipe tests' stderr to `dot(1)`, to render an SVG log
+
 EOF
 }
 
@@ -33,7 +37,7 @@ target=tests
 export BUILDTYPE=Test
 cmd="out/${BUILDTYPE}/${target}"
 
-while getopts "df:s:gGhpv" option; do
+while getopts "df:s:gGhpvS" option; do
   case ${option} in
     h)
       usage
@@ -61,6 +65,9 @@ while getopts "df:s:gGhpv" option; do
     s)
       export TREE_SITTER_SEED=${OPTARG}
       ;;
+    S)
+      mode=SVG
+      ;;
   esac
 done
 
@@ -92,6 +99,11 @@ case ${mode} in
     fi
     ;;
 
+  SVG)
+    $cmd "${args[@]}" 2> >(dot -Tsvg > index.html)
+    echo "Wrote index.html"
+    ;;
+
   normal)
     time $cmd "${args[@]}"
     ;;