std/streams/writer_from_stream_writer_test.ts

// Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.

import { assertEquals } from "../testing/asserts.ts";
import { writerFromStreamWriter } from "./writer_from_stream_writer.ts";

Deno.test("[streams] writerFromStreamWriter()", async function () {
  const written: string[] = [];
  const chunks: string[] = ["hello", "deno", "land"];
  const writableStream = new WritableStream({
    write(chunk) {
      const decoder = new TextDecoder();
      written.push(decoder.decode(chunk));
    },
  });

  const encoder = new TextEncoder();
  const writer = writerFromStreamWriter(writableStream.getWriter());

  for (const chunk of chunks) {
    const n = await writer.write(encoder.encode(chunk));
    // stream writers always write all the bytes
    assertEquals(n, chunk.length);
  }

  assertEquals(written, chunks);
});