Add tests for #69

tests/driver/native/src/lib.rs

@@ -72,6 +72,8 @@ pub mod jni {
         #[field]
         pub username: Field<'env, 'borrow, String>,
         pub password: String,
+        #[field]
+        pub bytes: Field<'env, 'borrow, Box<[i8]>>,
     }
 
     impl<'env: 'borrow, 'borrow> User<'env, 'borrow> {

tests/driver/src/main/java/User.java

@@ -15,6 +15,7 @@ public class User {
 
     private String username;
     private String password;
+    private byte[] bytes;
 
     @Override
     public String toString() {
@@ -155,6 +156,7 @@ public User(String username, String password) {
 
         this.username = username;
         this.password = password;
+        this.bytes = password.getBytes();
     }
 
     public static String getNullableString(String v) {

tests/mod.rs

@@ -253,6 +253,14 @@ fn vm_creation_and_object_usage() {
     assert_eq!("42__", User::cloneUser(&env, &borrow_user).password);
     // Mutable class fields work as expected
     assert_eq!("borrow__", borrow_user.username.get().expect("unable to get username"));
+    // This field is simply not updated on the java side
+    let expected = "42".as_bytes();
+    assert_eq!(
+        unsafe {
+            &*std::ptr::slice_from_raw_parts(expected.as_ref().as_ptr() as *const i8, expected.as_ref().len())
+        }.to_vec(),
+        borrow_user.bytes.get().expect("unable to get bytes").to_vec(),
+    );
 
     assert_eq!(borrow_user.toString(&env), "User{username='borrow__', password='42__'}");
     assert_eq!(borrow_user_opt.toString(&env), "User{username='borrow_opt____', password='42____'}");