Add skipped test for future improvement to createFacet.

packages/@react-facet/core/src/facet/createFacet.spec.ts

@@ -235,3 +235,24 @@ describe('setWithCallback', () => {
     expect(listenerMock).not.toHaveBeenCalled()
   })
 })
+
+describe('regressions', () => {
+  it.skip('only calls initial observer once for a facet with an initialValue and a startSubscription', () => {
+    const value = 'test-value'
+    const initialValue = 'initial-value'
+    const cleanup = jest.fn()
+    const startSubscription = jest.fn().mockImplementation((update) => {
+      update(value)
+      return cleanup
+    })
+
+    const mock = createFacet<string>({ startSubscription, initialValue })
+
+    const listener = jest.fn()
+
+    mock.observe(listener)
+
+    expect(listener).toHaveBeenCalledTimes(1)
+    expect(listener).toHaveBeenLastCalledWith(value)
+  })
+})