(send_data) Don't open an already open file

send_data.py

@@ -238,11 +238,11 @@ def check_all_data_is_saved(data_file, quiet=False):
         print('Wait a second and check that all the data has been sent')
     time.sleep(1)
 
-    with open(data_file.name, 'r') as file:
-        lines = file.readlines()
-        file_nb_line = len(lines) / 2
-        extract = json.loads(lines[1])
-        data_type = extract['type']
+    data_file.seek(0)
+    lines = data_file.readlines()
+    file_nb_line = int(len(lines) / 2)
+    extract = json.loads(lines[1])
+    data_type = extract['type']
 
     if not quiet:
         print("\tFound: {} lines in '{}' file".format(file_nb_line, data_file.name))