1 files changed, 40 insertions, 0 deletions
diff --git a/testing/web-platform/tests/speculation-rules/prerender/resources/session-history-test-util.js b/testing/web-platform/tests/speculation-rules/prerender/resources/session-history-test-util.js
new file mode 100644
index 0000000000..c1ca36dc2f
--- /dev/null
+++ b/testing/web-platform/tests/speculation-rules/prerender/resources/session-history-test-util.js
@@ -0,0 +1,40 @@
+// Note: Following utility functions are expected to be used from
+// session-history-* test files.
+
+async function waitChannelMessage(testName, uid) {
+  const result = new Promise((resolve) => {
+    const testChannel = new PrerenderChannel(testName, uid);
+    testChannel.addEventListener(
+      "message",
+      (e) => {
+        testChannel.close();
+        resolve(e.data);
+      },
+      { once: true },
+    );
+  });
+  return result;
+}
+
+async function runTestInPrerender(testName, uid) {
+  const result = waitChannelMessage(`test-channel-${testName}`, uid);
+
+  // Run test in a new window for test isolation.
+  const prerender = "session-history-prerender.https.html";
+  window.open(
+    `./resources/session-history-initiator.https.html?prerender=${prerender}&testName=${testName}&uid=${uid}`,
+    "_blank",
+    "noopener",
+  );
+  return result;
+}
+
+// This will activate the prerendered context created in runTestInPrerender
+// and then run the post-activation variation of `testName`.
+async function runTestInActivatedPage(testName, uid) {
+  const testChannel = new PrerenderChannel(`test-channel-${testName}`, uid);
+  testChannel.postMessage("activate");
+  testChannel.close();
+
+  return waitChannelMessage(`test-channel-${testName}`, uid);
+}