add tests

Author: P403n1x87

tests/test_cfg.py

@@ -82,16 +82,27 @@ def test_iter_invalid_types(self):
         block[:] = [nop]
         self.assertEqual(len(block), 1)
 
-        # Only one jump allowed and only at the end — caught at extend time
+        # Only one jump allowed and only at the end
         block = BasicBlock()
         block2 = BasicBlock()
+        # caught at extend time (within batch)
         with self.assertRaises(ValueError):
             block.extend(
                 [
                     Instr("JUMP_FORWARD", block2),
                     Instr("NOP"),
                 ]
             )
+        # caught at append time (cross-boundary)
+        block = BasicBlock()
+        block.append(Instr("JUMP_FORWARD", block2))
+        with self.assertRaises(ValueError):
+            block.append(Instr("NOP"))
+        # caught at extend time (cross-boundary)
+        block = BasicBlock()
+        block.append(Instr("JUMP_FORWARD", block2))
+        with self.assertRaises(ValueError):
+            block.extend([Instr("NOP")])
 
         # jump target must be a BasicBlock
         block = BasicBlock()