add test for stream util

apps/app/src/server/util/stream.integ.ts

@@ -0,0 +1,33 @@
+import { Readable, Writable, pipeline } from 'stream';
+import { promisify } from 'util';
+
+import { getBufferToFixedSizeTransform } from './stream'; // adjust the path as needed
+
+const pipelinePromise = promisify(pipeline);
+
+describe('stream util', () => {
+  describe('getBufferToFixedSizeTransform', () => {
+    it('should buffer data to fixed size and push to next stream', async() => {
+      const bufferSize = 10;
+      const chunks: Buffer[] = [];
+
+      const readable = Readable.from([Buffer.from('1234567890A'), Buffer.from('BCDE'), Buffer.from('FGH'), Buffer.from('IJKL')]);
+      const transform = getBufferToFixedSizeTransform(bufferSize);
+      const writable = new Writable({
+        write(chunk: Buffer, encoding, callback) {
+          chunks.push(chunk);
+          callback();
+        },
+      });
+
+      const expectedChunks = [Buffer.from('1234567890'), Buffer.from('ABCDEFGHIJ'), Buffer.from('KL')];
+
+      await pipelinePromise(readable, transform, writable);
+
+      expect(chunks).toHaveLength(expectedChunks.length);
+      expectedChunks.forEach((expectedChunk, index) => {
+        expect(chunks[index].toString()).toBe(expectedChunk.toString());
+      });
+    });
+  });
+});