fix: MediaFileUpload error if file does not exist (#1127)

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Fixes #798 🦕

googleapiclient/http.py

@@ -573,20 +573,22 @@ def __init__(
       resumable: bool, True if this is a resumable upload. False means upload
         in a single request.
     """
+        self._fd = None
         self._filename = filename
-        fd = open(self._filename, "rb")
+        self._fd = open(self._filename, "rb")
         if mimetype is None:
             # No mimetype provided, make a guess.
             mimetype, _ = mimetypes.guess_type(filename)
             if mimetype is None:
                 # Guess failed, use octet-stream.
                 mimetype = "application/octet-stream"
         super(MediaFileUpload, self).__init__(
-            fd, mimetype, chunksize=chunksize, resumable=resumable
+            self._fd, mimetype, chunksize=chunksize, resumable=resumable
         )
 
     def __del__(self):
-        self._fd.close()
+        if self._fd:
+            self._fd.close()
 
     def to_json(self):
         """Creating a JSON representation of an instance of MediaFileUpload.

tests/test_http.py

@@ -248,6 +248,10 @@ def test_media_file_upload_to_from_json(self):
         self.assertEqual(500, new_upload.chunksize())
         self.assertEqual(b"PNG", new_upload.getbytes(1, 3))
 
+    def test_media_file_upload_raises_on_file_not_found(self):
+        with self.assertRaises(FileNotFoundError):
+            MediaFileUpload(datafile("missing.png"))
+
     def test_media_file_upload_raises_on_invalid_chunksize(self):
         self.assertRaises(
             InvalidChunkSizeError,