test: early return when imports undefined

Author: kamilmysliwiec

packages/core/injector/topology-tree/topology-tree.ts

@@ -23,6 +23,9 @@ export class TopologyTree {
   }
 
   private traverseAndMapToTree(node: TreeNode<Module>, depth = 1) {
+    if (!node.value.imports) {
+      return;
+    }
     node.value.imports.forEach(child => {
       if (!child) {
         return;