Split test generator base class

The class BaseTarget served two purposes:
- track test cases and target files for generation
- provide an abstract base class for individual test groups

Splitting these allows decoupling these two and to have further common
superclasses across targets.

No intended change in generated test cases.

Signed-off-by: Janos Follath <janos.follath@arm.com>

scripts/mbedtls_dev/bignum_common.py

@@ -17,6 +17,8 @@
 from abc import abstractmethod
 from typing import Iterator, List, Tuple, TypeVar
 
+from . import test_data_generation
+
 T = TypeVar('T') #pylint: disable=invalid-name
 
 def invmod(a: int, n: int) -> int:
@@ -63,8 +65,7 @@ def combination_pairs(values: List[T]) -> List[Tuple[T, T]]:
     """Return all pair combinations from input values."""
     return [(x, y) for x in values for y in values]
 
-
-class OperationCommon:
+class OperationCommon(test_data_generation.BaseTest):
     """Common features for bignum binary operations.
 
     This adds functionality common in binary operation tests.

scripts/mbedtls_dev/bignum_core.py

@@ -16,20 +16,19 @@
 
 import random
 
-from abc import ABCMeta
 from typing import Dict, Iterator, List, Tuple
 
 from . import test_case
 from . import test_data_generation
 from . import bignum_common
 
-class BignumCoreTarget(test_data_generation.BaseTarget, metaclass=ABCMeta):
-    #pylint: disable=abstract-method
+class BignumCoreTarget(test_data_generation.BaseTarget):
+    #pylint: disable=abstract-method, too-few-public-methods
     """Target for bignum core test case generation."""
     target_basename = 'test_suite_bignum_core.generated'
 
 
-class BignumCoreShiftR(BignumCoreTarget, metaclass=ABCMeta):
+class BignumCoreShiftR(BignumCoreTarget, test_data_generation.BaseTest):
     """Test cases for mbedtls_bignum_core_shift_r()."""
     count = 0
     test_function = "mpi_core_shift_r"
@@ -69,7 +68,7 @@ class BignumCoreShiftR(BignumCoreTarget, metaclass=ABCMeta):
             for count in counts:
                 yield cls(input_hex, descr, count).create_test_case()
 
-class BignumCoreCTLookup(BignumCoreTarget, metaclass=ABCMeta):
+class BignumCoreCTLookup(BignumCoreTarget, test_data_generation.BaseTest):
     """Test cases for mbedtls_mpi_core_ct_uint_table_lookup()."""
     test_function = "mpi_core_ct_uint_table_lookup"
     test_name = "Constant time MPI table lookup"
@@ -107,7 +106,8 @@ class BignumCoreCTLookup(BignumCoreTarget, metaclass=ABCMeta):
                 yield (cls(bitsize, bitsize_description, window_size)
                        .create_test_case())
 
-class BignumCoreOperation(bignum_common.OperationCommon, BignumCoreTarget, metaclass=ABCMeta):
+class BignumCoreOperation(BignumCoreTarget, bignum_common.OperationCommon,
+                          metaclass=ABCMeta):
     #pylint: disable=abstract-method
     """Common features for bignum core operations."""
     input_values = [
@@ -297,7 +297,7 @@ class BignumCoreMLA(BignumCoreOperation):
                 yield cur_op.create_test_case()
 
 
-class BignumCoreMontmul(BignumCoreTarget):
+class BignumCoreMontmul(BignumCoreTarget, test_data_generation.BaseTest):
     """Test cases for Montgomery multiplication."""
     count = 0
     test_function = "mpi_core_montmul"

scripts/mbedtls_dev/bignum_mod.py

@@ -14,12 +14,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from abc import ABCMeta
-
 from . import test_data_generation
 
-class BignumModTarget(test_data_generation.BaseTarget, metaclass=ABCMeta):
-    #pylint: disable=abstract-method
+class BignumModTarget(test_data_generation.BaseTarget):
+    #pylint: disable=abstract-method, too-few-public-methods
     """Target for bignum mod test case generation."""
     target_basename = 'test_suite_bignum_mod.generated'
 

scripts/mbedtls_dev/bignum_mod_raw.py

@@ -21,8 +21,8 @@ from . import test_case
 from . import test_data_generation
 from . import bignum_common
 
-class BignumModRawTarget(test_data_generation.BaseTarget, metaclass=ABCMeta):
-    #pylint: disable=abstract-method
+class BignumModRawTarget(test_data_generation.BaseTarget):
+    #pylint: disable=abstract-method, too-few-public-methods
     """Target for bignum mod_raw test case generation."""
     target_basename = 'test_suite_bignum_mod_raw.generated'
 

scripts/mbedtls_dev/test_data_generation.py

@@ -25,6 +25,7 @@ import argparse
 import os
 import posixpath
 import re
+import inspect
 
 from abc import ABCMeta, abstractmethod
 from typing import Callable, Dict, Iterable, Iterator, List, Type, TypeVar
@@ -35,12 +36,8 @@ from . import test_case
 T = TypeVar('T') #pylint: disable=invalid-name
 
 
-class BaseTarget(metaclass=ABCMeta):
-    """Base target for test case generation.
-
-    Child classes of this class represent an output file, and can be referred
-    to as file targets. These indicate where test cases will be written to for
-    all subclasses of the file target, which is set by `target_basename`.
+class BaseTest(metaclass=ABCMeta):
+    """Base class for test case generation.
 
     Attributes:
         count: Counter for test cases from this class.
@@ -48,8 +45,6 @@ class BaseTarget(metaclass=ABCMeta):
             automatically generated using the class, or manually set.
         dependencies: A list of dependencies required for the test case.
         show_test_count: Toggle for inclusion of `count` in the test description.
-        target_basename: Basename of file to write generated tests to. This
-            should be specified in a child class of BaseTarget.
         test_function: Test function which the class generates cases for.
         test_name: A common name or description of the test function. This can
             be `test_function`, a clearer equivalent, or a short summary of the
@@ -59,7 +54,6 @@ class BaseTarget(metaclass=ABCMeta):
     case_description = ""
     dependencies = [] # type: List[str]
     show_test_count = True
-    target_basename = ""
     test_function = ""
     test_name = ""
 
@@ -121,6 +115,20 @@ class BaseTarget(metaclass=ABCMeta):
         """
         raise NotImplementedError
 
+
+class BaseTarget:
+    """Base target for test case generation.
+
+    Child classes of this class represent an output file, and can be referred
+    to as file targets. These indicate where test cases will be written to for
+    all subclasses of the file target, which is set by `target_basename`.
+
+    Attributes:
+        target_basename: Basename of file to write generated tests to. This
+            should be specified in a child class of BaseTarget.
+    """
+    target_basename = ""
+
     @classmethod
     def generate_tests(cls) -> Iterator[test_case.TestCase]:
         """Generate test cases for the class and its subclasses.
@@ -132,7 +140,7 @@ class BaseTarget(metaclass=ABCMeta):
         yield from `generate_tests()` in each. Calling this method on a class X
         will yield test cases from all classes derived from X.
         """
-        if cls.test_function:
+        if issubclass(cls, BaseTest) and not inspect.isabstract(cls):
             yield from cls.generate_function_tests()
         for subclass in sorted(cls.__subclasses__(), key=lambda c: c.__name__):
             yield from subclass.generate_tests()

tests/scripts/generate_bignum_tests.py

@@ -68,13 +68,13 @@ from mbedtls_dev import bignum_common
 # the framework
 from mbedtls_dev import bignum_core, bignum_mod_raw # pylint: disable=unused-import
 
-class BignumTarget(test_data_generation.BaseTarget, metaclass=ABCMeta):
-    #pylint: disable=abstract-method
+class BignumTarget(test_data_generation.BaseTarget):
     """Target for bignum (legacy) test case generation."""
     target_basename = 'test_suite_bignum.generated'
 
 
-class BignumOperation(bignum_common.OperationCommon, BignumTarget, metaclass=ABCMeta):
+class BignumOperation(bignum_common.OperationCommon, BignumTarget,
+                      metaclass=ABCMeta):
     #pylint: disable=abstract-method
     """Common features for bignum operations in legacy tests."""
     input_values = [