gh-87092: Expose assembler to unit tests (#103988)

Lib/test/test_compiler_assemble.py

@@ -0,0 +1,71 @@
+
+import ast
+import types
+
+from test.support.bytecode_helper import AssemblerTestCase
+
+
+# Tests for the code-object creation stage of the compiler.
+
+class IsolatedAssembleTests(AssemblerTestCase):
+
+    def complete_metadata(self, metadata, filename="myfile.py"):
+        if metadata is None:
+            metadata = {}
+        for key in ['name', 'qualname']:
+            metadata.setdefault(key, key)
+        for key in ['consts']:
+            metadata.setdefault(key, [])
+        for key in ['names', 'varnames', 'cellvars', 'freevars']:
+            metadata.setdefault(key, {})
+        for key in ['argcount', 'posonlyargcount', 'kwonlyargcount']:
+            metadata.setdefault(key, 0)
+        metadata.setdefault('firstlineno', 1)
+        metadata.setdefault('filename', filename)
+        return metadata
+
+    def assemble_test(self, insts, metadata, expected):
+        metadata = self.complete_metadata(metadata)
+        insts = self.complete_insts_info(insts)
+
+        co = self.get_code_object(metadata['filename'], insts, metadata)
+        self.assertIsInstance(co, types.CodeType)
+
+        expected_metadata = {}
+        for key, value in metadata.items():
+            if isinstance(value, list):
+                expected_metadata[key] = tuple(value)
+            elif isinstance(value, dict):
+                expected_metadata[key] = tuple(value.keys())
+            else:
+                expected_metadata[key] = value
+
+        for key, value in expected_metadata.items():
+            self.assertEqual(getattr(co, "co_" + key), value)
+
+        f = types.FunctionType(co, {})
+        for args, res in expected.items():
+            self.assertEqual(f(*args), res)
+
+    def test_simple_expr(self):
+        metadata = {
+            'filename' : 'avg.py',
+            'name'     : 'avg',
+            'qualname' : 'stats.avg',
+            'consts'   : [2],
+            'argcount' : 2,
+            'varnames' : {'x' : 0, 'y' : 1},
+        }
+
+        # code for "return (x+y)/2"
+        insts = [
+            ('RESUME', 0),
+            ('LOAD_FAST', 0, 1),   # 'x'
+            ('LOAD_FAST', 1, 1),   # 'y'
+            ('BINARY_OP', 0, 1),   # '+'
+            ('LOAD_CONST', 0, 1),  # 2
+            ('BINARY_OP', 11, 1),   # '/'
+            ('RETURN_VALUE', 1),
+        ]
+        expected = {(3, 4) : 3.5, (-100, 200) : 50, (10, 18) : 14}
+        self.assemble_test(insts, metadata, expected)