test(boxed_field): Box an oneof field (#1235)

tests/build.rs

@@ -170,6 +170,7 @@ fn main() {
 
     prost_build::Config::new()
         .boxed("Foo.bar")
+        .boxed("Foo.oneof_field.box_qux")
         .compile_protos(&[src.join("boxed_field.proto")], includes)
         .unwrap();
 

tests/src/boxed_field.proto

@@ -4,6 +4,10 @@ package boxed_field;
 
 message Foo {
   Bar bar = 1;
+  oneof oneof_field {
+    string baz = 2;
+    Bar box_qux = 3;
+  }
 }
 
 message Bar {

tests/src/boxed_field.rs

@@ -1,10 +1,17 @@
 include!(concat!(env!("OUT_DIR"), "/boxed_field.rs"));
 
+use self::foo::OneofField;
+
 #[test]
-/// Confirm `Foo::bar` is boxed by creating an instance
-fn test_bar_is_boxed() {
+/// Confirm `Foo::bar` and `OneofField::BoxQux` is boxed by creating an instance
+fn test_boxed_field() {
     use alloc::boxed::Box;
     let _ = Foo {
         bar: Some(Box::new(Bar {})),
+        oneof_field: Some(OneofField::BoxQux(Box::new(Bar {}))),
+    };
+    let _ = Foo {
+        bar: Some(Box::new(Bar {})),
+        oneof_field: Some(OneofField::Baz("hello".into())),
     };
 }