node: fix splitToEnd function returning invalid chunks in tests (NFC) (#305)

Co-authored-by: Sebastian Alex <sebastian.alex@saucelabs.com>

Author: perf2711

packages/node/tests/_helpers/chunks.ts

@@ -1,16 +1,30 @@
 import { Readable } from 'stream';
 import { ChunkSplitter } from '../../src/streams/chunkifier.js';
 
+/**
+ * Trims array from right until `predicate` returns `false`.
+ * @returns Trimmed array.
+ */
+function trimRightIf<T>(t: T[], predicate: (t: T) => boolean) {
+    for (let i = t.length - 1; i >= 0; i--) {
+        if (predicate(t[i])) {
+            continue;
+        }
+
+        return t.slice(0, i + 1);
+    }
+
+    return [];
+}
+
 export async function splitToEnd(readable: Readable, splitter: ChunkSplitter) {
     const results: Buffer[][] = [[]];
 
     for await (let chunk of readable) {
         while (chunk) {
             const [c1, c2] = splitter(chunk, readable.readableEncoding ?? 'utf-8');
             results[results.length - 1].push(c1);
-            if (!c2?.length) {
-                break;
-            } else if (c2) {
+            if (c2) {
                 chunk = c2;
                 results.push([]);
             } else {
@@ -19,7 +33,11 @@ export async function splitToEnd(readable: Readable, splitter: ChunkSplitter) {
         }
     }
 
-    return results.map((b) => Buffer.concat(b));
+    // Remove all trailing empty arrays
+    return trimRightIf(
+        results.map((b) => Buffer.concat(b)),
+        (t) => !t.length,
+    );
 }
 
 export function* chunkify(chunk: Buffer, length: number) {