test: reproduce dataChanged bug

#60

tests/tst_proxyroles.qml

@@ -55,6 +55,32 @@ Item {
         }
     }
 
+    ListModel {
+        id: singleRowModel
+        ListElement {
+            changingRole: "Change me"
+            otherRole: "I don't change"
+        }
+    }
+
+    SortFilterProxyModel {
+        id: noProxyRolesProxyModel
+        sourceModel: singleRowModel
+    }
+
+    Instantiator {
+        id: outerInstantiator
+        model: noProxyRolesProxyModel
+        QtObject {
+            property var counter: ({ count : 0 })
+            property string changingRole: model.changingRole
+            property string otherRole: {
+                ++counter.count;
+                return model.otherRole;
+            }
+        }
+    }
+
     TestCase {
         name: "ProxyRoles"
 
@@ -89,5 +115,12 @@ Item {
             compare(testModel.get(0, "role1"), "data for role1");
             compare(testModel.get(0, "role2"), "data for role2");
         }
+
+        function test_ProxyRolesDataChanged() {
+            outerInstantiator.object.counter.count = 0;
+            singleRowModel.setProperty(0, "changingRole", "Changed")
+            compare(outerInstantiator.object.changingRole, "Changed");
+            compare(outerInstantiator.object.counter.count, 0);
+        }
     }
 }