test: green up after Phase 2 merge for #26\n\n- Fix AST tests (is_override)\n- Align MIR builder test with current If AST\n- Adjust ResultBox API usage in tests\n- Add len() helpers to ArrayBox/BufferBox for tests

src/ast.rs

@@ -928,6 +928,7 @@ mod tests {
                 }
             ],
             is_static: false,  // 通常のメソッド
+            is_override: false,
             span: Span::unknown(),
         });
         
@@ -983,4 +984,4 @@ mod tests {
         assert!(binary_op.is_expression());
         assert!(binary_op.info().contains("+"));
     }
-}
+}