Add one more test for the assign-function

arcshift/src/lib.rs

@@ -440,10 +440,11 @@ impl<T: 'static> ArcShiftCell<T> {
 
     /// Assign the given ArcShift to this instance.
     /// This does not copy the value T, it replaces the ArcShift instance of Self
-    /// with a clone of 'other'.
+    /// with a clone of 'other'. It does not clone T, only the ArcShift holding it.
+    ///
     /// This returns Err if recursion is detected, and has no effect in this case.
     /// Recursion occurs if 'assign' is called from within the closure supplied to
-    /// the 'get'-function.
+    /// the 'ArcShiftCell::get'-function.
     pub fn assign(&self, other: &ArcShift<T>) -> Result<(), RecursionDetected> {
         if self.recursion.get() == 0 {
             // SAFETY:

arcshift/src/tests.rs

@@ -170,6 +170,7 @@ fn simple_cell() {
         owner.validate();
     });
 }
+
 #[test]
 fn simple_cell_recursion() {
     model(|| {
@@ -179,6 +180,7 @@ fn simple_cell_recursion() {
             let cell = ArcShiftCell::from_arcshift(root.clone());
             cell.get(|val| {
                 assert_eq!(val.str(), "root");
+                assert!(cell.assign(&ArcShift::new(owner.create("dummy"))).is_err());
                 cell.get(|val| {
                     assert_eq!(val.str(), "root");
                     root.update(owner.create("B"));