diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index d89542a..c23cb6b 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -68,6 +68,8 @@
             --directory ${CMAKE_CURRENT_BINARY_DIR}/suites
         DEPENDS
             ${CMAKE_CURRENT_SOURCE_DIR}/../tests/scripts/generate_bignum_tests.py
+            ${CMAKE_CURRENT_SOURCE_DIR}/../scripts/mbedtls_dev/bignum_common.py
+            ${CMAKE_CURRENT_SOURCE_DIR}/../scripts/mbedtls_dev/bignum_core.py
             ${CMAKE_CURRENT_SOURCE_DIR}/../scripts/mbedtls_dev/test_case.py
             ${CMAKE_CURRENT_SOURCE_DIR}/../scripts/mbedtls_dev/test_data_generation.py
     )
diff --git a/tests/Makefile b/tests/Makefile
index 57f8855..7c08f54 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -92,6 +92,8 @@
 .SECONDARY: generated_bignum_test_data generated_psa_test_data
 $(GENERATED_BIGNUM_DATA_FILES): generated_bignum_test_data
 generated_bignum_test_data: scripts/generate_bignum_tests.py
+generated_bignum_test_data: ../scripts/mbedtls_dev/bignum_common.py
+generated_bignum_test_data: ../scripts/mbedtls_dev/bignum_core.py
 generated_bignum_test_data: ../scripts/mbedtls_dev/test_case.py
 generated_bignum_test_data: ../scripts/mbedtls_dev/test_data_generation.py
 generated_bignum_test_data:
diff --git a/tests/scripts/generate_bignum_tests.py b/tests/scripts/generate_bignum_tests.py
index 7f332dc..1eec27b 100755
--- a/tests/scripts/generate_bignum_tests.py
+++ b/tests/scripts/generate_bignum_tests.py
@@ -54,34 +54,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import itertools
 import sys
-import typing
 
-from abc import ABCMeta, abstractmethod
-from typing import Iterator, List, Tuple, TypeVar
+from abc import ABCMeta
+from typing import Iterator
 
 import scripts_path # pylint: disable=unused-import
 from mbedtls_dev import test_case
 from mbedtls_dev import test_data_generation
-
-T = TypeVar('T') #pylint: disable=invalid-name
-
-def hex_to_int(val: str) -> int:
-    return int(val, 16) if val else 0
-
-def quote_str(val) -> str:
-    return "\"{}\"".format(val)
-
-def combination_pairs(values: List[T]) -> List[Tuple[T, T]]:
-    """Return all pair combinations from input values."""
-    # The return value is cast, as older versions of mypy are unable to derive
-    # the specific type returned by itertools.combinations_with_replacement.
-    return typing.cast(
-        List[Tuple[T, T]],
-        list(itertools.combinations_with_replacement(values, 2))
-    )
-
+from mbedtls_dev import bignum_common
+# Import modules containing additional test classes
+# Test function classes in these modules will be registered by
+# the framework
+from mbedtls_dev import bignum_core # pylint: disable=unused-import
 
 class BignumTarget(test_data_generation.BaseTarget, metaclass=ABCMeta):
     #pylint: disable=abstract-method
@@ -89,36 +74,14 @@
     target_basename = 'test_suite_mpi.generated'
 
 
-class BignumOperation(BignumTarget, metaclass=ABCMeta):
-    """Common features for bignum binary operations.
-
-    This adds functionality common in binary operation tests. This includes
-    generation of case descriptions, using descriptions of values and symbols
-    to represent the operation or result.
-
-    Attributes:
-        symbol: Symbol used for the operation in case description.
-        input_values: List of values to use as test case inputs. These are
-            combined to produce pairs of values.
-        input_cases: List of tuples containing pairs of test case inputs. This
-            can be used to implement specific pairs of inputs.
-    """
-    symbol = ""
+class BignumOperation(bignum_common.OperationCommon, BignumTarget, metaclass=ABCMeta):
+    #pylint: disable=abstract-method
+    """Common features for bignum operations in legacy tests."""
     input_values = [
         "", "0", "7b", "-7b",
         "0000000000000000123", "-0000000000000000123",
         "1230000000000000000", "-1230000000000000000"
-    ] # type: List[str]
-    input_cases = [] # type: List[Tuple[str, str]]
-
-    def __init__(self, val_a: str, val_b: str) -> None:
-        self.arg_a = val_a
-        self.arg_b = val_b
-        self.int_a = hex_to_int(val_a)
-        self.int_b = hex_to_int(val_b)
-
-    def arguments(self) -> List[str]:
-        return [quote_str(self.arg_a), quote_str(self.arg_b), self.result()]
+    ]
 
     def description(self) -> str:
         """Generate a description for the test case.
@@ -135,15 +98,6 @@
             )
         return super().description()
 
-    @abstractmethod
-    def result(self) -> str:
-        """Get the result of the operation.
-
-        This could be calculated during initialization and stored as `_result`
-        and then returned, or calculated when the method is called.
-        """
-        raise NotImplementedError
-
     @staticmethod
     def value_description(val) -> str:
         """Generate a description of the argument val.
@@ -168,20 +122,9 @@
         return tmp
 
     @classmethod
-    def get_value_pairs(cls) -> Iterator[Tuple[str, str]]:
-        """Generator to yield pairs of inputs.
-
-        Combinations are first generated from all input values, and then
-        specific cases provided.
-        """
-        yield from combination_pairs(cls.input_values)
-        yield from cls.input_cases
-
-    @classmethod
     def generate_function_tests(cls) -> Iterator[test_case.TestCase]:
         for a_value, b_value in cls.get_value_pairs():
-            cur_op = cls(a_value, b_value)
-            yield cur_op.create_test_case()
+            yield cls(a_value, b_value).create_test_case()
 
 
 class BignumCmp(BignumOperation):
@@ -221,7 +164,7 @@
     symbol = "+"
     test_function = "mpi_add_mpi"
     test_name = "MPI add"
-    input_cases = combination_pairs(
+    input_cases = bignum_common.combination_pairs(
         [
             "1c67967269c6", "9cde3",
             "-1c67967269c6", "-9cde3",
@@ -229,7 +172,8 @@
     )
 
     def result(self) -> str:
-        return quote_str("{:x}".format(self.int_a + self.int_b))
+        return bignum_common.quote_str("{:x}").format(self.int_a + self.int_b)
+
 
 if __name__ == '__main__':
     # Use the section of the docstring relevant to the CLI as description