Refactor code structure for improved readability and maintainability

backend/tests/predefinedActivityDrawingData.test.js

@@ -0,0 +1,20 @@
+import { describe, expect, it } from 'vitest';
+
+import { normalizeStoredDrawingData } from '../utils/drawingData.js';
+
+describe('predefined activity drawing data', () => {
+  it('stores drawing objects as JSON once', () => {
+    expect(normalizeStoredDrawingData({ selectedStartPosition: 'AS1' }))
+      .toBe('{"selectedStartPosition":"AS1"}');
+  });
+
+  it('does not double encode JSON text sent by mobile clients', () => {
+    expect(normalizeStoredDrawingData('{"strokeType":"VH"}'))
+      .toBe('{"strokeType":"VH"}');
+  });
+
+  it('repairs previously double encoded JSON text', () => {
+    expect(normalizeStoredDrawingData('"{\\"targetPosition\\":\\"5\\"}"'))
+      .toBe('{"targetPosition":"5"}');
+  });
+});