fix: Segmentation fault in tink while writing data (#1490)

* fix: Segmentation fault in tink while writing data

* add unit tests

Author: Pulkit0110

google/cloud/storage/_media/requests/download.py

@@ -387,7 +387,6 @@ def _write_to_stream(self, response):
                     msg += content_length_msg
                     raise DataCorruption(response, msg)
 
-
     def consume(
         self,
         transport,

google/cloud/storage/fileio.py

@@ -477,7 +477,7 @@ def write(self, b):
         self._buffer.seek(0, io.SEEK_END)
         pos = self._buffer.write(b)
         self._buffer.seek(bookmark)
-        return self._cursor + pos
+        return pos
 
     def read(self, size=-1):
         """Read and move the cursor."""

tests/unit/test_fileio.py

@@ -367,12 +367,14 @@ def test_write(self, mock_warn):
 
         # Write under chunk_size. This should be buffered and the upload not
         # initiated.
-        writer.write(TEST_BINARY_DATA[0:4])
+        w1 = writer.write(TEST_BINARY_DATA[0:4])
+        self.assertEqual(w1, 4)
         blob._initiate_resumable_upload.assert_not_called()
 
         # Write over chunk_size. This should result in upload initialization
         # and multiple chunks uploaded.
-        writer.write(TEST_BINARY_DATA[4:32])
+        w2 = writer.write(TEST_BINARY_DATA[4:32])
+        self.assertEqual(w2, 28)
         blob._initiate_resumable_upload.assert_called_once_with(
             blob.bucket.client,
             writer._buffer,