moveTo: check targetDirectory and more

- test for already moved file 1st (or 2nd) : testing a boolean can avoid heavier tests
- unify string and empty string in a single test: the exception message suggests both requirements

Author: pine3ree

src/UploadedFile.php

@@ -142,24 +142,26 @@ public function getStream()
      */
     public function moveTo($targetPath)
     {
-        if ($this->error !== UPLOAD_ERR_OK) {
-            throw new RuntimeException('Cannot retrieve stream due to upload error');
+        if ($this->moved) {
+            throw new RuntimeException('Cannot move file; already moved!');
         }
 
-        if (! is_string($targetPath)) {
-            throw new InvalidArgumentException(
-                'Invalid path provided for move operation; must be a string'
-            );
+        if ($this->error !== UPLOAD_ERR_OK) {
+            throw new RuntimeException('Cannot retrieve stream due to upload error');
         }
 
-        if (empty($targetPath)) {
+        if (! is_string($targetPath) || empty($targetPath)) {
             throw new InvalidArgumentException(
                 'Invalid path provided for move operation; must be a non-empty string'
             );
         }
 
-        if ($this->moved) {
-            throw new RuntimeException('Cannot move file; already moved!');
+        $targetDirectory = dirname($targetPath);
+        if (! is_dir($targetDirectory) || ! is_writable($targetDirectory)) {
+            throw new RuntimeException(sprintf(
+                'The target directory `%s` does not exists or is not writable',
+                $targetDirectory
+            ));
         }
 
         $sapi = PHP_SAPI;