diff --git a/shell/platform/darwin/desktop/main_mac.mm b/shell/platform/darwin/desktop/main_mac.mm
index 8087d0e92cd6d08441f572fc69806d05cd238124..808a5f63f1d145ac2fb4d731f77c5c971deddee6 100644
--- a/shell/platform/darwin/desktop/main_mac.mm
+++ b/shell/platform/darwin/desktop/main_mac.mm
@@ -7,13 +7,69 @@
 #include <iostream>
 
 #include "flutter/fml/message_loop.h"
+#include "flutter/shell/common/platform_view.h"
 #include "flutter/shell/common/shell.h"
 #include "flutter/shell/common/switches.h"
 #include "flutter/shell/platform/darwin/common/platform_mac.h"
 #include "flutter/shell/platform/darwin/desktop/flutter_application.h"
+#include "flutter/shell/testing/test_runner.h"
 #include "flutter/shell/testing/testing.h"
 #include "lib/fxl/command_line.h"
 #include "lib/fxl/logging.h"
+#include "lib/tonic/dart_microtask_queue.h"
+
+// Exit codes used by the Dart command line tool.
+const int kApiErrorExitCode = 253;
+const int kCompilationErrorExitCode = 254;
+const int kErrorExitCode = 255;
+
+// Checks whether the engine's main Dart isolate has no pending work.  If so,
+// then exit the given message loop.
+class ScriptCompletionTaskObserver : public fml::TaskObserver {
+ public:
+  ScriptCompletionTaskObserver(fxl::RefPtr<fxl::TaskRunner> task_runner)
+      : main_task_runner_(std::move(task_runner)),
+        prev_live_(false),
+        last_error_(tonic::kNoError) {}
+
+  void DidProcessTask() override {
+    shell::TestRunner& test_runner = shell::TestRunner::Shared();
+    shell::Engine& engine = test_runner.platform_view().engine();
+
+    if (engine.GetLoadScriptError() != tonic::kNoError) {
+      last_error_ = engine.GetLoadScriptError();
+      main_task_runner_->PostTask([]() { fml::MessageLoop::GetCurrent().Terminate(); });
+      return;
+    }
+
+    bool live = engine.UIIsolateHasLivePorts();
+    if (prev_live_ && !live) {
+      last_error_ = engine.GetUIIsolateLastError();
+      main_task_runner_->PostTask([]() { fml::MessageLoop::GetCurrent().Terminate(); });
+    }
+    prev_live_ = live;
+  }
+
+  tonic::DartErrorHandleType last_error() { return last_error_; }
+
+ private:
+  fxl::RefPtr<fxl::TaskRunner> main_task_runner_;
+  bool prev_live_;
+  tonic::DartErrorHandleType last_error_;
+};
+
+int ConvertErrorTypeToExitCode(tonic::DartErrorHandleType error) {
+  switch (error) {
+    case tonic::kCompilationErrorType:
+      return kCompilationErrorExitCode;
+    case tonic::kApiErrorType:
+      return kApiErrorExitCode;
+    case tonic::kUnknownErrorType:
+      return kErrorExitCode;
+    default:
+      return 0;
+  }
+}
 
 static fxl::CommandLine InitializedCommandLine() {
   std::vector<std::string> args_vector;
@@ -47,8 +103,31 @@ int main(int argc, const char* argv[]) {
   if (command_line.HasOption(shell::FlagForSwitch(shell::Switch::NonInteractive))) {
     if (!shell::InitForTesting(std::move(command_line)))
       return 1;
+
+    // Note that this task observer must be added after the observer that drains
+    // the microtask queue.
+    ScriptCompletionTaskObserver task_observer(fml::MessageLoop::GetCurrent().GetTaskRunner());
+    blink::Threads::UI()->PostTask(
+        [&task_observer] { fml::MessageLoop::GetCurrent().AddTaskObserver(&task_observer); });
+
     fml::MessageLoop::GetCurrent().Run();
-    return EXIT_SUCCESS;
+
+    shell::TestRunner& test_runner = shell::TestRunner::Shared();
+    tonic::DartErrorHandleType error = test_runner.platform_view().engine().GetLoadScriptError();
+    if (error == tonic::kNoError)
+      error = task_observer.last_error();
+    if (error == tonic::kNoError) {
+      fxl::AutoResetWaitableEvent latch;
+      blink::Threads::UI()->PostTask([&error, &latch] {
+        error = tonic::DartMicrotaskQueue::GetForCurrentThread()->GetLastError();
+        latch.Signal();
+      });
+      latch.Wait();
+    }
+
+    // The script has completed and the engine may not be in a clean state,
+    // so just stop the process.
+    exit(ConvertErrorTypeToExitCode(error));
   } else {
     return NSApplicationMain(argc, argv);
   }