Approval tests can use Catch path fixed in env. var, and convert nullptr and __null to 0 for comparison

scripts/scriptCommon.py

@@ -2,8 +2,13 @@ import os
 import sys
 import subprocess
 
+
 catchPath = os.path.dirname(os.path.realpath( os.path.dirname(sys.argv[0])))
 
+def getBuildExecutable():
+    dir = os.environ.get('CATCH_DEV_OUT_DIR', "cmake-build-debug/SelfTest")
+    return dir
+
 def runAndCapture( args ):
     child = subprocess.Popen(" ".join( args ), shell=True, stdout=subprocess.PIPE)
     lines = []
@@ -18,4 +23,4 @@ def runAndCapture( args ):
                 line = ""
             else:
                 line = line + out
-    return lines
+    return lines