diff --git a/engine/src/flutter/shell/testing/test_runner.cc b/engine/src/flutter/shell/testing/test_runner.cc
index 85770cbf956..28d2568ba22 100644
--- a/engine/src/flutter/shell/testing/test_runner.cc
+++ b/engine/src/flutter/shell/testing/test_runner.cc
@@ -15,8 +15,9 @@ namespace shell {
 
 TestRunner::TestRunner() : platform_view_(new PlatformViewTest()) {
   blink::ViewportMetrics metrics;
-  metrics.physical_width = 800;
-  metrics.physical_height = 600;
+  metrics.device_pixel_ratio = 3.0;
+  metrics.physical_width = 2400; // 800 at 3x resolution
+  metrics.physical_height = 1800; // 600 at 3x resolution
 
   blink::Threads::UI()->PostTask(
       [ engine = platform_view_->engine().GetWeakPtr(), metrics ] {