diff --git a/build/dart/dart_action.gni b/build/dart/dart_action.gni
index 6bd19d7fb0d..77a0130c1be 100644
--- a/build/dart/dart_action.gni
+++ b/build/dart/dart_action.gni
@@ -52,6 +52,10 @@ template("_compiled_action") {
       visibility = invoker.visibility
     }
 
+    if (defined(invoker.testonly)) {
+      testonly = invoker.testonly
+    }
+
     script = "$_dart_root/build/gn_run_binary.py"
 
     if (defined(invoker.inputs)) {
@@ -111,10 +115,11 @@ template("_prebuilt_tool_action") {
     not_needed(invoker, ["target"])
     action(target_name) {
       forward_variables_from(invoker, [
-          "outputs",
-          "deps",
-          "visibility",
           "depfile",
+          "deps",
+          "outputs",
+          "testonly",
+          "visibility",
       ])
       script = "$_dart_root/build/gn_run_binary.py"
 
@@ -148,11 +153,12 @@ template("_prebuilt_tool_action") {
     not_needed(invoker, ["binary"])
     _compiled_action(target_name) {
       forward_variables_from(invoker, [
+          "depfile",
+          "deps",
           "inputs",
           "outputs",
-          "deps",
+          "testonly",
           "visibility",
-          "depfile",
       ])
 
       if (defined(invoker.script)) {
@@ -200,6 +206,7 @@ template("_prebuilt_tool_action") {
 #    deps
 #    inputs
 #    outputs
+#    testonly
 #    visibility
 template("prebuilt_dart_action") {
   assert(defined(invoker.script), "script must be defined for $target_name")
@@ -253,6 +260,7 @@ template("_prebuilt_gen_snapshot_action") {
 #    deps
 #    inputs
 #    outputs
+#    testonly
 #    visibility
 template("_built_tool_action") {
   assert(defined(invoker.tool), "tool must be defined for $target_name")
@@ -273,6 +281,7 @@ template("_built_tool_action") {
         "inputs",
         "outputs",
         "tool",
+        "testonly",
         "visibility",
     ])
 
@@ -317,6 +326,7 @@ template("_built_tool_action") {
 #    deps
 #    inputs
 #    outputs
+#    testonly
 #    visibility
 template("dart_action") {
   assert(defined(invoker.script), "script must be defined for $target_name")
@@ -331,6 +341,7 @@ template("dart_action") {
         "outputs",
         "packages",
         "script",
+        "testonly",
         "tool",
         "visibility",
         "vm_args",
@@ -363,6 +374,7 @@ template("dart_action") {
 #    deps
 #    inputs
 #    outputs
+#    testonly
 #    visibility
 template("dart_bootstrap_action") {
   assert(defined(invoker.script), "script must be defined for $target_name")
@@ -377,6 +389,7 @@ template("dart_bootstrap_action") {
         "outputs",
         "packages",
         "script",
+        "testonly",
         "tool",
         "visibility",
         "vm_args",
@@ -408,6 +421,7 @@ template("dart_bootstrap_action") {
 #    deps
 #    inputs
 #    outputs
+#    testonly
 #    visibility
 template("gen_snapshot_action") {
   assert(!defined(invoker.script),
@@ -422,6 +436,7 @@ template("gen_snapshot_action") {
         "inputs",
         "outputs",
         "packages",
+        "testonly",
         "tool",
         "visibility",
         "vm_args",