Add increase/decrease support test (#5224)

api/cpp/include/slint-testing.h

@@ -195,6 +195,44 @@ public:
         }
     }
 
+    /// Invokes the increase accessibility action of that element
+    /// (`accessible-action-increment`).
+    void invoke_accessible_increment_action() const
+    {
+        if (auto item = private_api::upgrade_item_weak(inner)) {
+            union IncreaseActionHelper {
+                cbindgen_private::AccessibilityAction action;
+                IncreaseActionHelper()
+                {
+                    action.tag = cbindgen_private::AccessibilityAction::Tag::Increment;
+                }
+                ~IncreaseActionHelper() { }
+
+            } action;
+            item->item_tree.vtable()->accessibility_action(item->item_tree.borrow(), item->index,
+                                                           &action.action);
+        }
+    }
+
+    /// Invokes the decrease accessibility action of that element
+    /// (`accessible-action-decrement`).
+    void invoke_accessible_decrement_action() const
+    {
+        if (auto item = private_api::upgrade_item_weak(inner)) {
+            union DecreaseActionHelper {
+                cbindgen_private::AccessibilityAction action;
+                DecreaseActionHelper()
+                {
+                    action.tag = cbindgen_private::AccessibilityAction::Tag::Decrement;
+                }
+                ~DecreaseActionHelper() { }
+
+            } action;
+            item->item_tree.vtable()->accessibility_action(item->item_tree.borrow(), item->index,
+                                                           &action.action);
+        }
+    }
+
     /// Invokes the default accessibility action of that element
     /// (`accessible-action-default`).
     void invoke_accessible_default_action() const

internal/backends/testing/search_api.rs

@@ -174,4 +174,20 @@ impl ElementHandle {
             })
             .unwrap_or_default()
     }
+
+    /// Increase value of the element's `accessible-action-increment` property. Note that you can only set this
+    /// property if it is declared in your Slint code.
+    pub fn invoke_accessible_increment_action(&self) {
+        if let Some(item) = self.0.upgrade() {
+            item.accessible_action(&AccessibilityAction::Increment)
+        }
+    }
+
+    /// Decrease value of the element's `accessible-action-decrease` property. Note that you can only set this
+    /// property if it is declared in your Slint code.
+    pub fn invoke_accessible_decrement_action(&self) {
+        if let Some(item) = self.0.upgrade() {
+            item.accessible_action(&AccessibilityAction::Decrement)
+        }
+    }
 }

tests/cases/widgets/spinbox_default_value.slint

@@ -41,6 +41,12 @@ assert_eq!(spinbox.accessible_value_maximum(), Some(100f32));
 assert_eq!(spinbox.accessible_value_minimum(), Some(10f32));
 assert_eq!(spinbox.accessible_value_step(), Some(0.9));
 
+spinbox.invoke_accessible_increment_action();
+assert_eq!(spinbox.accessible_value().unwrap(), "11");
+
+spinbox.invoke_accessible_decrement_action();
+assert_eq!(spinbox.accessible_value().unwrap(), "10");
+
 
 ```
 
@@ -54,6 +60,12 @@ assert_eq(spinbox.accessible_value_maximum().value(), 100);
 assert_eq(spinbox.accessible_value_minimum().value(), 10);
 assert_eq(spinbox.accessible_value_step().value(), 0.9);
 
+spinbox.invoke_accessible_increment_action();
+assert_eq(spinbox.accessible_value().value(), "11");
+
+spinbox.invoke_accessible_decrement_action();
+assert_eq(spinbox.accessible_value().value(), "10");
+
 ```
 
 */