VDMS hangs when the test "ImageTest.ImageLoop" is run and the udf_server doesn't return a valid value in "/image" POST due to an invalid response message

[rolandoquesada]

Describe the bug
VDMS keeps in an infinite loop when it doesn't receive a valid response from the udf_server "/image" POST service

To Reproduce
Steps to reproduce the behavior:

1. Open the udf_server.py file located at tests/remote_function_test directory.

2. Locate the "/image" POST service in that udf_server.py file

3. Comment or remove all the code of that function and add a new line which returns an empty string (return "")
   

4. Run the ImageTest tests with the following command in the tests directory
   

5. Verify the testing gets frozen/hangs when the test called "ImageTest.ImageLoop" is run
   

Expected behavior
The test called "ImageTest.ImageLoop" should fail and VDMS should handle correctly the invalid response from the udf_server.