1 files changed, 75 insertions, 0 deletions
diff --git a/testing/web-platform/tests/speculation-rules/prerender/resources/session-history-harness.js b/testing/web-platform/tests/speculation-rules/prerender/resources/session-history-harness.js
new file mode 100644
index 0000000000..619ee3aa92
--- /dev/null
+++ b/testing/web-platform/tests/speculation-rules/prerender/resources/session-history-harness.js
@@ -0,0 +1,75 @@
+// We don't have the test harness in this context, so we roll our own
+// which communicates with our initiator which is actually running the tests.
+
+function assert(condition, message) {
+  if (!condition) {
+    throw new Error("Assertion failed: " + message);
+  }
+}
+
+// Run a test after activation.
+document.addEventListener("prerenderingchange", async (_) => {
+  // history.length is racy on activation. Wait *100ms* as a workaround.
+  // See crbug.com/1222893.
+  await new Promise((resolve) => {
+    window.setTimeout(resolve, 100);
+  });
+
+  const urlParams = new URLSearchParams(window.location.search);
+  const testName = urlParams.get("testName");
+  const uid = urlParams.get("uid");
+  const testChannel = new PrerenderChannel(
+    `test-channel-${testName}`, uid
+  );
+
+  try {
+    const activationTestFn = testName + "Activation";
+    const testFn = window[activationTestFn];
+    if (!testFn) {
+      testChannel.postMessage("Missing test: " + testName);
+      return;
+    }
+    testFn();
+    testChannel.postMessage("Passed");
+  } catch (e) {
+    testChannel.postMessage(
+      "Failed: " + e.name + ": " + e.message,
+    );
+  } finally {
+    testChannel.close();
+  }
+})
+
+if (document.prerendering) {
+  window.onload = async () => {
+    const urlParams = new URLSearchParams(window.location.search);
+    const testName = urlParams.get("testName");
+    const uid = urlParams.get("uid");
+    const prerenderChannel = new PrerenderChannel(
+      `prerender-channel-${testName}`, uid
+    );
+
+    // The document load event is not finished at this point, so navigations
+    // would be done with replacement. This interferes with our tests. We wait
+    // for the next task before navigating to avoid this.
+    await new Promise((resolve) => {
+      window.setTimeout(resolve);
+    });
+
+    try {
+      let testFn = window[testName];
+      if (!testFn) {
+        prerenderChannel.postMessage("Missing test: " + testName);
+        return;
+      }
+      await testFn();
+      prerenderChannel.postMessage("Passed");
+    } catch (e) {
+      prerenderChannel.postMessage(
+        "Failed: " + e.name + ": " + e.message,
+      );
+    } finally {
+      prerenderChannel.close();
+    }
+  };
+}