File reader fixes for verbs

- Fix local file reader to always read in chunks
- Have gzip stream raise an exception if the full data is requested

storage/local.py

@@ -61,9 +61,11 @@ class LocalStorage(BaseStorageV2):
         num_bytes < 0 copy until the stream ends.
     """
     bytes_copied = 0
-    bytes_remaining = num_bytes
-    while bytes_remaining > 0 or num_bytes < 0:
-      size_to_read = min(bytes_remaining, self.buffer_size)
+    while bytes_copied < num_bytes or num_bytes == -1:
+      size_to_read = min(num_bytes - bytes_copied, self.buffer_size)
+      if size_to_read < 0:
+        size_to_read = self.buffer_size
+
       try:
         buf = in_fp.read(size_to_read)
         if not buf: