Raise NotImplementedError in abstract methods

Signed-off-by: Werner Lewis <werner.lewis@arm.com>

scripts/mbedtls_dev/test_generation.py

@@ -67,7 +67,7 @@ class BaseTarget(metaclass=ABCMeta):
         Returns:
             List of arguments required for the test function.
         """
-        pass
+        raise NotImplementedError
 
     def description(self) -> str:
         """Create a test description.
@@ -104,7 +104,7 @@ class BaseTarget(metaclass=ABCMeta):
         of the class with appropriate input data, and then calling
         `create_test_case()` on each.
         """
-        pass
+        raise NotImplementedError
 
     @classmethod
     def generate_tests(cls) -> Iterator[test_case.TestCase]:

tests/scripts/generate_bignum_tests.py

@@ -122,7 +122,7 @@ class BignumOperation(BignumTarget, metaclass=ABCMeta):
         This may be calculated during initialization and stored as `_result`,
         or calculated when the method is called.
         """
-        pass
+        raise NotImplementedError
 
     @staticmethod
     def value_description(val) -> str: