Allow StreamInterface as raw HTTP Client body

Since the body payload is passed through to Guzzle, which in turn can
handle Streams as well, this extends the versatility of the HTTP Client

src/Illuminate/Http/Client/PendingRequest.php

@@ -78,7 +78,7 @@ class PendingRequest
     /**
      * The raw body for the request.
      *
-     * @var string
+     * @var string|\Psr\Http\Message\StreamInterface
      */
     protected $pendingBody;
 
@@ -259,7 +259,7 @@ public function baseUrl(string $url)
     /**
      * Attach a raw body to the request.
      *
-     * @param  string  $content
+     * @param  string|\Psr\Http\Message\StreamInterface  $content
      * @param  string  $contentType
      * @return $this
      */

tests/Http/HttpClientTest.php

@@ -6,6 +6,7 @@
 use GuzzleHttp\Middleware;
 use GuzzleHttp\Promise\PromiseInterface;
 use GuzzleHttp\Psr7\Response as Psr7Response;
+use GuzzleHttp\Psr7\Utils;
 use GuzzleHttp\TransferStats;
 use Illuminate\Contracts\Events\Dispatcher;
 use Illuminate\Contracts\Support\Arrayable;
@@ -357,6 +358,26 @@ public function testSendRequestBodyWithManyAmpersands()
         $this->factory->withBody($body, 'text/plain')->send('post', 'http://foo.com/api');
     }
 
+    public function testSendStreamRequestBody()
+    {
+        $string = 'Look at me, i am a stream!!';
+        $resource = fopen('php://temp', 'w');
+        fwrite($resource, $string);
+        rewind($resource);
+        $body = Utils::streamFor($resource);
+
+        $fakeRequest = function (Request $request) use ($body, $string) {
+            self::assertSame($string, $request->body());
+            self::assertContains('text/plain', $request->header('Content-Type'));
+
+            return ['my' => 'response'];
+        };
+
+        $this->factory->fake($fakeRequest);
+
+        $this->factory->withBody($body, 'text/plain')->send('post', 'http://foo.com/api');
+    }
+
     public function testUrlsCanBeStubbedByPath()
     {
         $this->factory->fake([