Implemented factory pattern for trace transformers

src/testcrush/grammars/transformers.py

@@ -2,8 +2,9 @@
 # SPDX-License-Identifier: MIT
 
 import lark
+import pathlib
 
-from typing import Literal, Any, Iterable
+from typing import Literal, Any, Iterable, Union
 from testcrush.zoix import Fault
 from testcrush.utils import get_logger
 
@@ -312,3 +313,27 @@ def reg_and_mem(self, *reg_val_pairs: str) -> str:
         """
         reg_and_mem = f"\"{', '.join([ str(pair).strip() for pair in reg_val_pairs])}\""
         return reg_and_mem
+
+
+class TraceTransformerFactory:
+    """
+    Factory pattern for trace transformers and the corresponding grammars.
+
+    To be used as ``transformer, grammar = TraceTransformerFactory("ProcessorString")``
+    """
+    _current_directory = pathlib.Path(__file__).parent
+    _transformers = {
+        "CV32E40P": (TraceTransformerCV32E40P, _current_directory / "trace_cv32e40p.lark")
+    }
+
+    def __call__(self, processor_type: str) -> Union[tuple[TraceTransformerCV32E40P, str]]:
+
+        transformer, grammar = self._transformers.get(processor_type, (None, None))
+
+        if not transformer:
+            raise KeyError(f"Transformer for {processor_type} not found")
+
+        with open(grammar) as src:
+            lark_grammar = src.read()
+
+        return transformer(), lark_grammar

src/unit_tests/test_transformers.py

@@ -20,7 +20,7 @@
 class FaultListTransformerTest(unittest.TestCase):
 
     grammar = open("../testcrush/grammars/fault_list.lark").read()
-    maxDiff = None
+
     def get_parser(self):
 
         return lark.Lark(grammar=self.grammar, start="start", parser="lalr", transformer=transformers.FaultListTransformer())
@@ -148,11 +148,11 @@ def test_small_delay_defects_fault_list(self):
 
 class TraceTransformerCV32E40PTest(unittest.TestCase):
 
-    grammar = open("../testcrush/grammars/trace_cv32e40p.lark").read()
-
     def get_parser(self):
 
-        return lark.Lark(grammar=self.grammar, start="start", parser="lalr", transformer=transformers.TraceTransformerCV32E40P())
+        factory = transformers.TraceTransformerFactory()
+        transformer, grammar = factory("CV32E40P")
+        return lark.Lark(grammar=grammar, start="start", parser="lalr", transformer=transformer)
 
     def test_doc_example(self):