Add deterministic tests

frontend/deterministic-tests/src/run-with-concurrency.ts

@@ -0,0 +1,33 @@
+export async function runWithConcurrency<T, R>(
+    items: T[],
+    concurrency: number,
+    fn: (item: T) => Promise<R>
+): Promise<R[]> {
+    const results: R[] = [];
+    const errors: unknown[] = [];
+    const executing = new Set<Promise<void>>();
+
+    for (let i = 0; i < items.length; i++) {
+        const index = i;
+        const p = fn(items[index])
+            .then((result) => {
+                results[index] = result;
+            })
+            .catch((error: unknown) => {
+                errors.push(error);
+            })
+            .finally(() => executing.delete(p));
+        executing.add(p);
+        if (executing.size >= concurrency) {
+            await Promise.race(executing);
+        }
+    }
+
+    // eslint-disable-next-line no-restricted-properties
+    await Promise.all(executing);
+
+    if (errors.length > 0) {
+        throw errors[0];
+    }
+    return results;
+}