1 files changed, 49 insertions, 0 deletions
diff --git a/image/test/mochitest/test_mq_dynamic_svg.html b/image/test/mochitest/test_mq_dynamic_svg.html
new file mode 100644
index 0000000000..25b708224e
--- /dev/null
+++ b/image/test/mochitest/test_mq_dynamic_svg.html
@@ -0,0 +1,49 @@
+<!DOCTYPE html>
+<meta charset=utf-8>
+<title>Dynamic changes to prefers-color-scheme affecting SVG images</title>
+<link rel=stylesheet type=text/css href=/tests/SimpleTest/test.css>
+<script src=/tests/SimpleTest/SimpleTest.js></script>
+<script src=/tests/SimpleTest/WindowSnapshot.js></script>
+<body onload=run()>
+<iframe id=f1 width=300 height=600></iframe>
+<iframe id=f2 width=300 height=600></iframe>
+<script>
+SimpleTest.waitForExplicitFinish();
+
+// Not strictly needed, but keeps eslint happy.
+let f1 = window.f1;
+let f2 = window.f2;
+
+function snapshotsEqual() {
+  let s1 = snapshotWindow(f1.contentWindow);
+  let s2 = snapshotWindow(f2.contentWindow);
+  return compareSnapshots(s1, s2, true)[0];
+}
+
+function waitForColorSchemeToBe(scheme) {
+  return new Promise(resolve => {
+    let mq = matchMedia(`(prefers-color-scheme: ${scheme})`);
+    if (mq.matches) {
+      resolve();
+    } else {
+      mq.addEventListener("change", resolve, { once: true });
+    }
+  });
+}
+
+async function run() {
+  let loadedFrame1 = new Promise(resolve => f1.onload = resolve);
+  let loadedFrame2 = new Promise(resolve => f2.onload = resolve);
+  await SpecialPowers.pushPrefEnv({ set: [["layout.css.prefers-color-scheme.content-override", 1]] });
+  await waitForColorSchemeToBe("light");
+  f1.src = "mq_dynamic_svg_test.html";
+  f2.src = "mq_dynamic_svg_ref.html";
+  await loadedFrame1;
+  await loadedFrame2;
+  ok(!snapshotsEqual(), "In light mode snapshot comparison should be false");
+  await SpecialPowers.pushPrefEnv({ set: [["layout.css.prefers-color-scheme.content-override", 0]] });
+  await waitForColorSchemeToBe("dark");
+  ok(snapshotsEqual(), "In dark mode snapshot comparison should be true");
+  SimpleTest.finish();
+}
+</script>