1 files changed, 52 insertions, 0 deletions
diff --git a/testing/web-platform/tests/html/browsers/browsing-the-web/overlapping-navigations-and-traversals/resources/helpers.mjs b/testing/web-platform/tests/html/browsers/browsing-the-web/overlapping-navigations-and-traversals/resources/helpers.mjs
new file mode 100644
index 0000000000..7938497920
--- /dev/null
+++ b/testing/web-platform/tests/html/browsers/browsing-the-web/overlapping-navigations-and-traversals/resources/helpers.mjs
@@ -0,0 +1,52 @@
+export function createIframe(t) {
+  return new Promise((resolve, reject) => {
+    const iframe = document.createElement("iframe");
+    iframe.onload = () => resolve(iframe);
+    iframe.onerror = () => reject(new Error("Could not load iframe"));
+    iframe.src = "/common/blank.html";
+
+    t.add_cleanup(() => iframe.remove());
+    document.body.append(iframe);
+  });
+}
+
+export function delay(t, ms) {
+  return new Promise(resolve => t.step_timeout(resolve, ms));
+}
+
+export function waitForLoad(obj) {
+  return new Promise(resolve => {
+    obj.addEventListener("load", resolve, { once: true });
+  });
+}
+
+export function waitForHashchange(obj) {
+  return new Promise(resolve => {
+    obj.addEventListener("hashchange", resolve, { once: true });
+  });
+}
+
+export function waitForPopstate(obj) {
+  return new Promise(resolve => {
+    obj.addEventListener("popstate", resolve, { once: true });
+  });
+}
+
+// This is used when we want to end the test by asserting some load doesn't
+// happen, but we're not sure how long to wait. We could just wait a long-ish
+// time (e.g. a second), but that makes the tests slow. Instead, assume that
+// network loads take roughly the same time. Then, you can use this function to
+// wait a small multiple of the duration of a separate iframe load; this should
+// be long enough to catch any problems.
+export async function waitForPotentialNetworkLoads(t) {
+  const before = performance.now();
+
+  // Sometimes we're doing something, like a traversal, which cancels our first
+  // attempt at iframe loading. In that case we bail out after 100 ms and try
+  // again. (Better ideas welcome...)
+  await Promise.race([createIframe(t), delay(t, 100)]);
+  await createIframe(t);
+
+  const after = performance.now();
+  await delay(t, after - before);
+}