1 files changed, 15 insertions, 0 deletions
diff --git a/testing/web-platform/mozilla/tests/dom/fs/support/testHelpers.js b/testing/web-platform/mozilla/tests/dom/fs/support/testHelpers.js
new file mode 100644
index 0000000000..5cf47435c1
--- /dev/null
+++ b/testing/web-platform/mozilla/tests/dom/fs/support/testHelpers.js
@@ -0,0 +1,15 @@
+async function waitUntil(isWaitDone, untilMs, stepMs = 25) {
+  const startMs = Date.now();
+
+  return new Promise((resolve, reject) => {
+      const areWeDoneYet = setInterval(async function() {
+        if (await isWaitDone()) {
+          clearInterval(areWeDoneYet);
+          resolve();
+        } else if (Date.now() > startMs + untilMs) {
+          clearInterval(areWeDoneYet);
+          reject(new Error("Timed out after " + untilMs + "ms"));
+        }
+      }, stepMs);
+  });
+}