PDFObjectTest.php: move test code to a separate test function

tests/PHPUnit/Integration/PDFObjectTest.php

@@ -291,10 +291,20 @@ public function testFormatContent(): void
         $cleaned = $formatContent->invoke($this->getPdfObjectInstance(new Document()), $content);
 
         $this->assertEquals('', $cleaned);
+    }
+
+    /**
+     * Check that escaped slashes and parentheses are accounted for,
+     * formatContent would emit a PHP Warning for "regular expression
+     * is too large" here without fix for issue #709
+     *
+     * @see https://github.com/smalot/pdfparser/issues/709
+     */
+    public function testFormatContentIssue709()
+    {
+        $formatContent = new \ReflectionMethod('Smalot\PdfParser\PDFObject', 'formatContent');
+        $formatContent->setAccessible(true);
 
-        // Check that escaped slashes and parentheses are accounted for;
-        // formatContent would emit a PHP Warning for "regular expression
-        // is too large" here without fix for Issue #709
         $content = '(String \\\\\\(string)Tj '.str_repeat('(Test)Tj ', 4500);
         $cleaned = $formatContent->invoke($this->getPdfObjectInstance(new Document()), $content);