diff --git a/runtime/fixtures/simple_main.dart b/runtime/fixtures/simple_main.dart
index dc744d2777e3bfdcf0f23ee25fcaea0c379564c3..55187d8642bfac24c7acdb24213e70050ab6a551 100644
--- a/runtime/fixtures/simple_main.dart
+++ b/runtime/fixtures/simple_main.dart
@@ -2,6 +2,6 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
-void simple_main() {
+void main() {
   print("Hello");
 }
diff --git a/shell/platform/embedder/fixtures/simple_main.dart b/shell/platform/embedder/fixtures/simple_main.dart
index 05a37e98348adb708ef82d1249750472d457b8c5..ab73b3a234abf58d9009026cfa184dd11ca56bf2 100644
--- a/shell/platform/embedder/fixtures/simple_main.dart
+++ b/shell/platform/embedder/fixtures/simple_main.dart
@@ -1 +1 @@
-void main() {}
\ No newline at end of file
+void main() {}
diff --git a/shell/platform/embedder/tests/embedder_unittests.cc b/shell/platform/embedder/tests/embedder_unittests.cc
index 6cd3f4d330a6501fc3b0940e542a56361c8d02c9..266cf92e55a4407c72d71f2fb69ca6ee850ee5c6 100644
--- a/shell/platform/embedder/tests/embedder_unittests.cc
+++ b/shell/platform/embedder/tests/embedder_unittests.cc
@@ -22,17 +22,14 @@ TEST(EmbedderTest, CanLaunchAndShutdownWithValidProjectArgs) {
     return false;
   };
 
-  std::string main =
-      std::string(testing::GetFixturesPath()) + "/simple_main.dart";
-
   FlutterRendererConfig config = {};
   config.type = FlutterRendererType::kSoftware;
   config.software = renderer;
 
   FlutterProjectArgs args = {};
   args.struct_size = sizeof(FlutterProjectArgs);
-  args.assets_path = "";
-  args.main_path = main.c_str();
+  args.assets_path = testing::GetFixturesPath();
+  args.main_path = "";
   args.packages_path = "";
 
   FlutterEngine engine = nullptr;
diff --git a/testing/testing.gni b/testing/testing.gni
index ad5badfe922fe4dc1652b7dfa7e074a827f27bd2..e653933b62a8499a400889b5477915fd8b11c953 100644
--- a/testing/testing.gni
+++ b/testing/testing.gni
@@ -2,18 +2,21 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+import("//third_party/dart/build/dart/dart_action.gni")
+
+# Builds test fixtures for a unit test.
+#
+# Generates a directory structure containing an assets directory and the Dart
+# code to execute compiled to kernel, emitted to assets/kernel_blob.bin.
 template("test_fixtures") {
   testonly = true
 
   assert(defined(invoker.fixtures), "Test fixtures must be specified.")
 
-  fixtures_name_target_name = target_name + "_gen_fixtures_name"
-  fixtures_source_set_target_name = target_name + "_gen_fixtures_source_set"
-  fixtures_copy_target_name = target_name + "_copy_fixtures"
-
-  fixtures_location = "$target_gen_dir/fixtures"
-  fixtures_location_file = "$target_gen_dir/test_fixtures_location.cc"
+  fixtures_location = "$target_gen_dir/$target_name/assets"
+  fixtures_location_file = "$target_gen_dir/$target_name/test_fixtures_location.cc"
 
+  fixtures_name_target_name = target_name + "_gen_fixtures_name"
   action(fixtures_name_target_name) {
     script = "$flutter_root/testing/build/gen_fixtures_location_symbol.py"
 
@@ -29,7 +32,9 @@ template("test_fixtures") {
     ]
   }
 
+  fixtures_source_set_target_name = target_name + "_gen_fixtures_source_set"
   source_set(fixtures_source_set_target_name) {
+    testonly = true
     sources = [
       fixtures_location_file,
     ]
@@ -39,16 +44,32 @@ template("test_fixtures") {
     ]
   }
 
-  copy(fixtures_copy_target_name) {
-    sources = invoker.fixtures
-    outputs = [
-      "$fixtures_location/{{source_file_part}}",
+  fixtures_kernel_target_name = target_name + "_kernel"
+  dart_action(fixtures_kernel_target_name) {
+    testonly = true
+    script = "$root_out_dir/frontend_server.dart.snapshot"
+
+    fixture_paths = []
+    foreach(fixture, invoker.fixtures) {
+      fixture_paths += [ rebase_path(fixture) ]
+    }
+    inputs = fixture_paths
+    outputs = ["$fixtures_location/kernel_blob.bin"]
+
+    args = [
+      "--sdk-root", rebase_path("$root_out_dir/flutter_patched_sdk"),
+      "--target", "flutter",
+      "--output-dill", rebase_path("$fixtures_location/kernel_blob.bin"),
+    ] + fixture_paths
+    deps = [
+      "//third_party/dart/utils/kernel-service:frontend_server"
     ]
   }
 
   group(target_name) {
+    testonly = true
     deps = [
-      ":$fixtures_copy_target_name",
+      ":$fixtures_kernel_target_name",
       ":$fixtures_source_set_target_name",
     ]
   }