Added test case for context filter with radius option

src/class_diagram/model/diagram.h

@@ -175,6 +175,15 @@ public:
     template <typename ElementT>
     opt_ref<ElementT> find(diagram_element::id_t id) const;
 
+    /**
+     * @brief Get reference to vector of elements of specific type
+     *
+     * @tparam ElementT Type of elements view
+     * @return Reference to elements vector
+     */
+    template <typename ElementT>
+    const common::reference_vector<ElementT> &elements() const;
+
     /**
      * @brief Add element to the diagram at a specified nested path.
      *
@@ -383,6 +392,12 @@ opt_ref<ElementT> diagram::find(diagram_element::id_t id) const
     return {};
 }
 
+template <typename ElementT>
+const common::reference_vector<ElementT> &diagram::elements() const
+{
+    return element_view<ElementT>::view();
+}
+
 //
 // Template method specialization pre-declarations...
 //