tc-testing: better test case file error reporting

tdc.py reads a bunch of test cases in json files.  When a json file
cannot be parsed, tdc just exits and does not run any tests.

This patch will cause tdc to print a message with the file name and
line number, then that file will be ignored and the rest of the tests
will be processed.
Signed-off-by: Brenda J. Butler <bjb@mojatatu.com>
Acked-by: Lucas Bates <lucasb@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/tc-testing/tdc.py

@@ -179,11 +179,16 @@ def has_blank_ids(idlist):
 
 def load_from_file(filename):
     """
-    Open the JSON file containing the test cases and return them as an
-    ordered dictionary object.
+    Open the JSON file containing the test cases and return them
+    as list of ordered dictionary objects.
     """
+    try:
         with open(filename) as test_data:
             testlist = json.load(test_data, object_pairs_hook=OrderedDict)
+    except json.JSONDecodeError as jde:
+        print('IGNORING test case file {}\n\tBECAUSE:  {}'.format(filename, jde))
+        testlist = list()
+    else:
         idlist = get_id_list(testlist)
         if (has_blank_ids(idlist)):
             for k in testlist: