Attempt to fix lazy loader spec transient failure

2 files changed, 44 insertions, 0 deletions

diff --git a/spec/javascripts/helpers/scroll_into_view_promise.js b/spec/javascripts/helpers/scroll_into_view_promise.js
new file mode 100644
index 00000000000..0edea2103da
--- /dev/null
+++ b/spec/javascripts/helpers/scroll_into_view_promise.js
@@ -0,0 +1,28 @@
+export default function scrollIntoViewPromise(intersectionTarget, timeout = 100, maxTries = 5) {
+  return new Promise((resolve, reject) => {
+    let intersectionObserver;
+    let retry = 0;
+
+    const intervalId = setInterval(() => {
+      if (retry >= maxTries) {
+        intersectionObserver.disconnect();
+        clearInterval(intervalId);
+        reject(new Error(`Could not scroll target into viewPort within ${timeout * maxTries} ms`));
+      }
+      retry += 1;
+      intersectionTarget.scrollIntoView();
+    }, timeout);
+
+    intersectionObserver = new IntersectionObserver(entries => {
+      if (entries[0].isIntersecting) {
+        intersectionObserver.disconnect();
+        clearInterval(intervalId);
+        resolve();
+      }
+    });
+
+    intersectionObserver.observe(intersectionTarget);
+
+    intersectionTarget.scrollIntoView();
+  });
+}
diff --git a/spec/javascripts/helpers/wait_for_attribute_change.js b/spec/javascripts/helpers/wait_for_attribute_change.js
new file mode 100644
index 00000000000..8f22d569222
--- /dev/null
+++ b/spec/javascripts/helpers/wait_for_attribute_change.js
@@ -0,0 +1,16 @@
+export default (domElement, attributes, timeout = 1500) =>
+  new Promise((resolve, reject) => {
+    let observer;
+    const timeoutId = setTimeout(() => {
+      observer.disconnect();
+      reject(new Error(`Could not see an attribute update within ${timeout} ms`));
+    }, timeout);
+
+    observer = new MutationObserver(() => {
+      clearTimeout(timeoutId);
+      observer.disconnect();
+      resolve();
+    });
+
+    observer.observe(domElement, { attributes: true, attributeFilter: attributes });
+  });