diff --git a/tests/streaming.test.ts b/tests/streaming.test.ts
index 839d8199..4a3ff99e 100644
--- a/tests/streaming.test.ts
+++ b/tests/streaming.test.ts
@@ -1,7 +1,7 @@
-import { PassThrough } from 'stream';
 import assert from 'assert';
 import { Stream, _iterSSEMessages } from 'writer-sdk/streaming';
 import { APIConnectionError } from 'writer-sdk/error';
+import { ReadableStreamFrom } from 'writer-sdk/internal/shims';
 
 describe('streaming decoding', () => {
   test('basic', async () => {
@@ -11,7 +11,7 @@ describe('streaming decoding', () => {
       yield Buffer.from('\n');
     }
 
-    const stream = _iterSSEMessages(new Response(await iteratorToStream(body())), new AbortController())[
+    const stream = _iterSSEMessages(new Response(ReadableStreamFrom(body())), new AbortController())[
       Symbol.asyncIterator
     ]();
 
@@ -29,7 +29,7 @@ describe('streaming decoding', () => {
       yield Buffer.from('\n');
     }
 
-    const stream = _iterSSEMessages(new Response(await iteratorToStream(body())), new AbortController())[
+    const stream = _iterSSEMessages(new Response(ReadableStreamFrom(body())), new AbortController())[
       Symbol.asyncIterator
     ]();
 
@@ -48,7 +48,7 @@ describe('streaming decoding', () => {
       yield Buffer.from('\n');
     }
 
-    const stream = _iterSSEMessages(new Response(await iteratorToStream(body())), new AbortController())[
+    const stream = _iterSSEMessages(new Response(ReadableStreamFrom(body())), new AbortController())[
       Symbol.asyncIterator
     ]();
 
@@ -69,7 +69,7 @@ describe('streaming decoding', () => {
       yield Buffer.from('\n');
     }
 
-    const stream = _iterSSEMessages(new Response(await iteratorToStream(body())), new AbortController())[
+    const stream = _iterSSEMessages(new Response(ReadableStreamFrom(body())), new AbortController())[
       Symbol.asyncIterator
     ]();
 
@@ -97,7 +97,7 @@ describe('streaming decoding', () => {
       yield Buffer.from('\n');
     }
 
-    const stream = _iterSSEMessages(new Response(await iteratorToStream(body())), new AbortController())[
+    const stream = _iterSSEMessages(new Response(ReadableStreamFrom(body())), new AbortController())[
       Symbol.asyncIterator
     ]();
 
@@ -126,7 +126,7 @@ describe('streaming decoding', () => {
       yield Buffer.from('\n\n');
     }
 
-    const stream = _iterSSEMessages(new Response(await iteratorToStream(body())), new AbortController())[
+    const stream = _iterSSEMessages(new Response(ReadableStreamFrom(body())), new AbortController())[
       Symbol.asyncIterator
     ]();
 
@@ -147,7 +147,7 @@ describe('streaming decoding', () => {
       yield Buffer.from('\n\n');
     }
 
-    const stream = _iterSSEMessages(new Response(await iteratorToStream(body())), new AbortController())[
+    const stream = _iterSSEMessages(new Response(ReadableStreamFrom(body())), new AbortController())[
       Symbol.asyncIterator
     ]();
 
@@ -172,7 +172,7 @@ describe('streaming decoding', () => {
       yield Buffer.from('\n');
     }
 
-    const stream = _iterSSEMessages(new Response(await iteratorToStream(body())), new AbortController())[
+    const stream = _iterSSEMessages(new Response(ReadableStreamFrom(body())), new AbortController())[
       Symbol.asyncIterator
     ]();
 
@@ -205,7 +205,7 @@ describe('streaming decoding', () => {
       yield Buffer.from('\n');
     }
 
-    const stream = _iterSSEMessages(new Response(await iteratorToStream(body())), new AbortController())[
+    const stream = _iterSSEMessages(new Response(ReadableStreamFrom(body())), new AbortController())[
       Symbol.asyncIterator
     ]();
 
@@ -240,27 +240,3 @@ test('error handling', async () => {
   );
   await err.toBeInstanceOf(APIConnectionError);
 });
-
-async function iteratorToStream(iterator: AsyncGenerator<any>): Promise<PassThrough> {
-  const parts: unknown[] = [];
-
-  for await (const chunk of iterator) {
-    parts.push(chunk);
-  }
-
-  let index = 0;
-
-  const stream = new PassThrough({
-    read() {
-      const value = parts[index];
-      if (value === undefined) {
-        stream.end();
-      } else {
-        index += 1;
-        stream.write(value);
-      }
-    },
-  });
-
-  return stream;
-}