test: it should not recompute derived atom when the async getter valu…

…e is the same

tests/vanilla/dependency.test.tsx

@@ -153,3 +153,24 @@ it('keeps atoms mounted between recalculations', async () => {
     unmounted: 0,
   })
 })
+
+it('should not recompute derived atom when the async getter value is the same', async () => {
+  const baseAtom = atom({ id: 0, value: 0 })
+  const derivedAsyncAtom = atom(async (get) => get(baseAtom).id)
+
+  const store = createStore()
+  async function updateValue() {
+    const { id, value } = await store.get(baseAtom)
+    store.set(baseAtom, { id, value: value + 1 })
+  }
+
+  let recomputeCount = 0
+  store.sub(derivedAsyncAtom, () => {
+    recomputeCount++
+  })
+  expect(recomputeCount).toBe(0)
+  await updateValue()
+  expect(recomputeCount).toBe(1)
+  await updateValue()
+  expect(recomputeCount).toBe(1)
+})