An Upload.Adapter that keeps track of uploaded files in memory, so that you can make assertions.

Example

test "files are uploaded" do
  assert {:ok, _} = start_supervised(Upload.Adapters.Test)
  assert {:ok, upload} = Upload.cast_path("/path/to/file.txt")
  assert {:ok, upload} = Upload.transfer(upload)
  assert map_size(Upload.Adapters.Test.get_uploads()) == 1
end