diff --git a/src/public/app/widgets/view_widgets/calendar_view.spec.ts b/src/public/app/widgets/view_widgets/calendar_view.spec.ts
new file mode 100644
index 000000000..2989091a6
--- /dev/null
+++ b/src/public/app/widgets/view_widgets/calendar_view.spec.ts
@@ -0,0 +1,114 @@
+import $ from "jquery";
+(window as any).$ = $;
+
+import { beforeAll, describe, it, vi } from "vitest";
+import utils from "../../services/utils.js";
+
+interface NoteDefinition {
+    title: string;
+    [key: string]: string;
+}
+
+async function buildNotes(notes: NoteDefinition[]) {
+    const ids = [];
+
+    for (const noteDef of notes) {
+        const FNote = (await import("../../entities/fnote.js")).default;
+        const FAttribute = (await import("../../entities/fattribute.js")).default;
+        const froca = (await import("../../services/froca.js")).default;
+
+        const fakeNoteId = utils.randomString(6);
+        const note = new FNote(froca, {
+            noteId: fakeNoteId,
+            title: noteDef.title,
+            type: "text",
+            mime: "text/html",
+            isProtected: false,
+            blobId: ""
+        });
+        froca.notes[note.noteId] = note;
+        ids.push(note.noteId);
+
+        let position = 0;
+        for (const [ key, value ] of Object.entries(noteDef)) {
+            if (key.startsWith("#")) {
+                const attributeId = utils.randomString(12);
+                const attribute = new FAttribute(froca, {
+                    noteId: note.noteId,
+                    attributeId: attributeId,
+                    type: "label",
+                    name: key.substring(1),
+                    value: value,
+                    position: position,
+                    isInheritable: false
+                });
+                froca.attributes[attributeId] = attribute;
+                note.attributes.push(attributeId);
+            }
+
+            position++;
+        }
+
+        console.log("Attributes", note.getOwnedAttributes());
+    }
+
+    return ids;
+}
+
+describe("Building events", () => {
+
+    beforeAll(async () => {
+        (window as any).WebSocket = () => {};
+        (window as any).glob = {
+            isMainWindow: true
+        };
+
+        vi.mock("../../services/ws.js", () => {
+            return {
+                default: {
+                    subscribeToMessages(callback: (message: unknown) => void) {
+                        // Do nothing.
+                    }
+                }
+            }
+        });
+
+        vi.mock("../../services/server.js", () => {
+            return {
+                default: {
+                    async get(url: string) {
+                        if (url === "options") {
+                            return {};
+                        }
+
+                        if (url === "keyboard-actions") {
+                            return [];
+                        }
+
+                        if (url === "tree") {
+                            return {
+                                branches: [],
+                                notes: [],
+                                attributes: []
+                            }
+                        }
+                    }
+                }
+            };
+        });
+    });
+
+    it("supports start date", async () => {
+        const noteIds = await buildNotes([
+            { title: "A", "#startDate": "2025-05-05" }
+        ]);
+
+        // import CalendarView from "./calendar_view.js";
+        const FNote = (await import("../../entities/fnote.js")).default;
+        const froca = (await import("../../services/froca.js"));
+        const CalendarView = (await import("./calendar_view.js")).default;
+        const events = CalendarView.buildEvents(noteIds);
+        console.log(noteIds, events);
+    });
+
+});
diff --git a/src/public/app/widgets/view_widgets/calendar_view.ts b/src/public/app/widgets/view_widgets/calendar_view.ts
index 749af00b0..5f5ffddf8 100644
--- a/src/public/app/widgets/view_widgets/calendar_view.ts
+++ b/src/public/app/widgets/view_widgets/calendar_view.ts
@@ -108,7 +108,7 @@ export default class CalendarView extends ViewMode {
 
         let eventBuilder: EventSourceFunc;
         if (!this.isCalendarRoot) {
-            eventBuilder = async () => await this.#buildEvents(this.noteIds)
+            eventBuilder = async () => await CalendarView.buildEvents(this.noteIds)
         } else {
             eventBuilder = async (e: EventSourceFuncArg) => await this.#buildEventsForCalendar(e);
         }
@@ -294,7 +294,7 @@ export default class CalendarView extends ViewMode {
         return events.flat();
     }
 
-    async #buildEvents(noteIds: string[]) {
+    static async buildEvents(noteIds: string[]) {
         const notes = await froca.getNotes(noteIds);
         const events: EventSourceInput = [];
 
@@ -302,7 +302,7 @@ export default class CalendarView extends ViewMode {
             const startDate = CalendarView.#getCustomisableLabel(note, "startDate", "calendar:startDate");
 
             if (note.hasChildren()) {
-                const childrenEventData = await this.#buildEvents(note.getChildNoteIds());
+                const childrenEventData = await this.buildEvents(note.getChildNoteIds());
                 if (childrenEventData.length > 0) {
                     events.push(childrenEventData);
                 }