fix: added a missing test, corrected the imports, added behavior for disconnected goals as last step

ref: N25B-434

src/pages/VisProgPage/visualProgrammingUI/components/Plan.tsx

@@ -1,5 +1,6 @@
-import { GoalReduce } from "../nodes/GoalNode"
 import { type Node } from "@xyflow/react"
+import { GoalReduce } from "../nodes/GoalNode"
+
 
 export type Plan = {
     name: string,

src/pages/VisProgPage/visualProgrammingUI/components/PlanEditingFunctions.tsx

@@ -27,8 +27,9 @@ export function insertGoalInPlan(plan: Plan, goalNode: GoalNode): Plan {
  * @param goalID: the goal node to delete.
  * @returns: a new plan with the goal removed.
  */
-export function deleteGoalInPlanByID(plan: Plan, goalID: string): Plan {
-    return {...plan,
+export function deleteGoalInPlanByID(plan: Plan, goalID: string) {
+    const updatedPlan = {...plan,
         steps: plan.steps.filter((x) => x.id !== goalID)
     }
+    return updatedPlan.steps.length == 0 ? undefined : updatedPlan
 }

src/pages/VisProgPage/visualProgrammingUI/nodes/BasicBeliefNode.tsx

@@ -6,7 +6,7 @@ import {
 import { Toolbar } from '../components/NodeComponents';
 import styles from '../../VisProg.module.css';
 import {MultiConnectionHandle} from "../components/RuleBasedHandle.tsx";
-import {allowOnlyConnectionsFromType} from "../HandleRules.ts";
+import {allowOnlyConnectionsFromHandle} from "../HandleRules.ts";
 import useFlowStore from '../VisProgStores';
 import { TextField } from '../../../../components/TextField';
 import { MultilineTextField } from '../../../../components/MultilineTextField';
@@ -185,7 +185,7 @@ export default function BasicBeliefNode(props: NodeProps<BasicBeliefNode>) {
           </div>
           )}
         <MultiConnectionHandle type="source" position={Position.Right} id="source" rules={[
-          allowOnlyConnectionsFromType(["norm", "trigger"]),
+        allowOnlyConnectionsFromHandle([{nodeType:"trigger",handleId:"TriggerBeliefs"}, {nodeType:"norm",handleId:"NormBeliefs"}]),
         ]}/>
       </div>
     </>

src/pages/VisProgPage/visualProgrammingUI/nodes/NormNode.tsx

@@ -80,7 +80,7 @@ export default function NormNode(props: NodeProps<NormNode>) {
       <MultiConnectionHandle type="source" position={Position.Right} id="norms" rules={[
         allowOnlyConnectionsFromHandle([{nodeType:"phase",handleId:"data"}])
       ]}/>
-      <SingleConnectionHandle type="target" position={Position.Bottom} id="beliefs" rules={[
+      <SingleConnectionHandle type="target" position={Position.Bottom} id="NormBeliefs" rules={[
         allowOnlyConnectionsFromType(["basic_belief"])
       ]}/>
     </div>

src/pages/VisProgPage/visualProgrammingUI/nodes/TriggerNode.tsx

@@ -69,7 +69,7 @@ export default function TriggerNode(props: NodeProps<TriggerNode>) {
       <SingleConnectionHandle
         type="target"
         position={Position.Bottom}
-        id="beliefs"
+        id="TriggerBeliefs"
         style={{ left: '40%' }} 
         rules={[
           allowOnlyConnectionsFromType(['basic_belief']),