test: add AutoPlaceUtil type tests

lib/features/auto-place/AutoPlaceUtil.spec.ts

@@ -0,0 +1,29 @@
+import Diagram from '../../Diagram';
+
+import ElementFactory from '../../core/ElementFactory';
+
+import {
+  findFreePosition,
+  generateGetNextPosition,
+  getConnectedDistance
+} from './AutoPlaceUtil';
+
+const diagram = new Diagram();
+
+const elementFactory = diagram.get<ElementFactory>('elementFactory');
+
+const source = elementFactory.createShape(),
+      element = elementFactory.createShape();
+
+const getNextPosition = generateGetNextPosition({ x: 100, y: 100 });
+
+findFreePosition(source, element, { x: 100, y: 100 }, getNextPosition);
+
+getConnectedDistance(source, {
+  defaultDistance: 100,
+  direction: 'right',
+  filter: (connection) => true,
+  getWeight: (connection) => 1,
+  maxDistance: 100,
+  reference: 'center'
+});