feat(course-registry): add course ownership transfer

contracts/course-registry/src/lib.rs

@@ -32,6 +32,15 @@ pub struct CourseStatusChanged {
     pub active: bool,
 }
 
+#[contractevent]
+pub struct OwnershipTransferred {
+    #[topic]
+    pub course_id: u32,
+    #[topic]
+    pub previous_instructor: Address,
+    pub new_instructor: Address,
+}
+
 #[contractevent]
 pub struct ModuleCompleted {
     #[topic]
@@ -234,6 +243,40 @@ impl CourseRegistry {
         env.storage().persistent().get(&key).unwrap_or(0)
     }
 
+    /// Transfers ownership of a course to a new instructor address.
+    /// Only callable by the current instructor of the course.
+    pub fn transfer_ownership(
+        env: Env,
+        current_instructor: Address,
+        new_instructor: Address,
+        course_id: u32,
+    ) {
+        let mut course: Course = env
+            .storage()
+            .persistent()
+            .get(&DataKey::Course(course_id))
+            .expect("Course not found");
+
+        assert!(
+            course.instructor == current_instructor,
+            "Unauthorized: Caller is not the course instructor"
+        );
+
+        current_instructor.require_auth();
+
+        course.instructor = new_instructor.clone();
+        env.storage()
+            .persistent()
+            .set(&DataKey::Course(course_id), &course);
+
+        OwnershipTransferred {
+            course_id,
+            previous_instructor: current_instructor,
+            new_instructor,
+        }
+        .publish(&env);
+    }
+
     /// Records a learner's completion of a module after off-chain quiz validation.
     /// Only callable by the authorized verifier (protocol admin).
     pub fn complete_module(env: Env, verifier: Address, learner: Address, id: u32) {

contracts/course-registry/src/test.rs

@@ -563,3 +563,87 @@ fn test_get_progress_tracks_completion() {
     client.complete_module(&admin, &learner, &course_id);
     assert_eq!(client.get_progress(&learner, &course_id), 3);
 }
+
+// ── transfer_ownership ────────────────────────────────────────────────────────
+
+#[test]
+fn test_transfer_ownership_success() {
+    let (env, client) = setup();
+    let (_, instructor, id) = setup_with_course(&env, &client);
+    let new_instructor = Address::generate(&env);
+
+    client.transfer_ownership(&instructor, &new_instructor, &id);
+
+    let course = client.get_course(&id);
+    assert_eq!(course.instructor, new_instructor);
+}
+
+#[test]
+fn test_transfer_ownership_emits_event() {
+    let (env, client) = setup();
+    let (_, instructor, id) = setup_with_course(&env, &client);
+    let new_instructor = Address::generate(&env);
+
+    client.transfer_ownership(&instructor, &new_instructor, &id);
+
+    // One OwnershipTransferred event must have been emitted
+    assert_eq!(env.events().all().len(), 1);
+}
+
+#[test]
+#[should_panic(expected = "Unauthorized: Caller is not the course instructor")]
+fn test_transfer_ownership_non_instructor_panics() {
+    let (env, client) = setup();
+    let (_, _, id) = setup_with_course(&env, &client);
+    let impostor = Address::generate(&env);
+    let new_instructor = Address::generate(&env);
+
+    client.transfer_ownership(&impostor, &new_instructor, &id);
+}
+
+#[test]
+#[should_panic(expected = "Course not found")]
+fn test_transfer_ownership_nonexistent_course_panics() {
+    let (env, client) = setup();
+    let admin = Address::generate(&env);
+    let instructor = Address::generate(&env);
+    let new_instructor = Address::generate(&env);
+
+    client.initialize(&admin);
+
+    client.transfer_ownership(&instructor, &new_instructor, &99);
+}
+
+#[test]
+fn test_transfer_ownership_new_instructor_can_update_metadata() {
+    let (env, client) = setup();
+    let (_, instructor, id) = setup_with_course(&env, &client);
+    let new_instructor = Address::generate(&env);
+
+    client.transfer_ownership(&instructor, &new_instructor, &id);
+
+    // New instructor must be able to update metadata after ownership transfer
+    let updated_hash = BytesN::from_array(&env, &[9u8; 32]);
+    client.update_metadata(&id, &updated_hash);
+
+    let course = client.get_course(&id);
+    assert_eq!(course.metadata_hash, updated_hash);
+}
+
+#[test]
+fn test_transfer_ownership_updates_instructor_field() {
+    let (env, client) = setup();
+    let (_, instructor, id) = setup_with_course(&env, &client);
+    let new_instructor = Address::generate(&env);
+
+    // Confirm original instructor before transfer
+    let before = client.get_course(&id);
+    assert_eq!(before.instructor, instructor);
+
+    client.transfer_ownership(&instructor, &new_instructor, &id);
+
+    // Confirm instructor field reflects the new address after transfer
+    let after = client.get_course(&id);
+    assert_eq!(after.instructor, new_instructor);
+    assert_ne!(after.instructor, instructor);
+}