python accessing freed shared memory object (#1253)

* added a 'isValid' member in shared memory (also updated shm version) with default true, any access to shared memory() checks also for validity. any free will set this to false and then unmap shm. Any access to shm will then check validity in python.

* fixed tests for shm

* added tests in python as well

---------

Co-authored-by: Alice <alice.mazzoleni@psi.ch>

tests/scripts/utils_for_test.py

@@ -9,7 +9,7 @@ from enum import Enum
 from colorama import Fore, Style, init
 from datetime import timedelta
 
-from slsdet import Detector, detectorSettings, burstMode
+from slsdet import Detector, Ctb, detectorSettings, burstMode
 from slsdet.defines import DEFAULT_TCP_RX_PORTNO, DEFAULT_UDP_DST_PORTNO
 SERVER_START_PORTNO=1900
 
@@ -167,9 +167,12 @@ def startDetectorVirtualServer(name :str, num_mods, fp):
                 time.sleep(3)
 
 
-def connectToVirtualServers(name, num_mods):
+def connectToVirtualServers(name, num_mods, ctb_object=False):
     try:
-        d = Detector()
+        if ctb_object:
+            d = Ctb()
+        else:
+            d = Detector()
     except Exception as e:
         raise RuntimeException(f'Could not create Detector object for {name}. Error: {str(e)}') from e