Improve multipart limits test

The PR introducing this test assumed time would be enough to accurately predict behavior. This commit changes it to using introspection to check the exact state of the parser and expected state once finished parsing a multipart request body. To accomplish that it was required to make the cursor in the file an object property, so it can be inspected using reflection.

src/Io/MultipartParser.php

@@ -73,6 +73,7 @@ final class MultipartParser
     private $postCount = 0;
     private $filesCount = 0;
     private $emptyCount = 0;
+    private $cursor = 0;
 
     /**
      * @param int|string|null $uploadMaxFilesize
@@ -112,6 +113,7 @@ public function parse(ServerRequestInterface $request)
         $request = $this->request;
         $this->request = null;
         $this->multipartBodyPartCount = 0;
+        $this->cursor = 0;
         $this->postCount = 0;
         $this->filesCount = 0;
         $this->emptyCount = 0;
@@ -125,20 +127,20 @@ private function parseBody($boundary, $buffer)
         $len = \strlen($boundary);
 
         // ignore everything before initial boundary (SHOULD be empty)
-        $start = \strpos($buffer, $boundary . "\r\n");
+        $this->cursor = \strpos($buffer, $boundary . "\r\n");
 
-        while ($start !== false) {
+        while ($this->cursor !== false) {
             // search following boundary (preceded by newline)
             // ignore last if not followed by boundary (SHOULD end with "--")
-            $start += $len + 2;
-            $end = \strpos($buffer, "\r\n" . $boundary, $start);
+            $this->cursor += $len + 2;
+            $end = \strpos($buffer, "\r\n" . $boundary, $this->cursor);
             if ($end === false) {
                 break;
             }
 
             // parse one part and continue searching for next
-            $this->parsePart(\substr($buffer, $start, $end - $start));
-            $start = $end;
+            $this->parsePart(\substr($buffer, $this->cursor, $end - $this->cursor));
+            $this->cursor = $end;
 
             if (++$this->multipartBodyPartCount > $this->maxMultipartBodyParts) {
                 break;

tests/Io/MultipartParserTest.php

@@ -1029,26 +1029,41 @@ public function testPostMaxFileSizeIgnoredByFilesComingBeforeIt()
 
     public function testWeOnlyParseTheAmountOfMultiPartChunksWeConfigured()
     {
+        $chunkCount = 5000000;
         $boundary = "---------------------------12758086162038677464950549563";
 
         $chunk = "--$boundary\r\n";
         $chunk .= "Content-Disposition: form-data; name=\"f\"\r\n";
         $chunk .= "\r\n";
         $chunk .= "u\r\n";
         $data = '';
-        for ($i = 0; $i < 5000000; $i++) {
-            $data .= $chunk;
-        }
+        $data .= str_repeat($chunk, $chunkCount);
         $data .= "--$boundary--\r\n";
 
         $request = new ServerRequest('POST', 'http://example.com/', array(
             'Content-Type' => 'multipart/form-data; boundary=' . $boundary,
         ), $data, 1.1);
 
         $parser = new MultipartParser();
-        $startTime = microtime(true);
-        $parser->parse($request);
-        $runTime = microtime(true) - $startTime;
-        $this->assertLessThan(1, $runTime);
+
+        $reflectecClass = new \ReflectionClass('\React\Http\Io\MultipartParser');
+        $requestProperty = $reflectecClass->getProperty('request');
+        $requestProperty->setAccessible(true);
+        $cursorProperty = $reflectecClass->getProperty('cursor');
+        $cursorProperty->setAccessible(true);
+        $multipartBodyPartCountProperty = $reflectecClass->getProperty('multipartBodyPartCount');
+        $multipartBodyPartCountProperty->setAccessible(true);
+        $maxMultipartBodyPartsProperty = $reflectecClass->getProperty('maxMultipartBodyParts');
+        $maxMultipartBodyPartsProperty->setAccessible(true);
+        $parseBodyMethod = $reflectecClass->getMethod('parseBody');
+        $parseBodyMethod->setAccessible(true);
+
+        $this->assertSame(0, $cursorProperty->getValue($parser));
+
+        $requestProperty->setValue($parser, $request);
+        $parseBodyMethod->invoke($parser, '--' . $boundary, $data);
+
+        $this->assertSame(strlen(str_repeat($chunk, $multipartBodyPartCountProperty->getValue($parser))), $cursorProperty->getValue($parser) + 2);
+        $this->assertSame($multipartBodyPartCountProperty->getValue($parser), $maxMultipartBodyPartsProperty->getValue($parser) + 1);
     }
 }