From 0209385eb0d76667f3f90c835e03a9d412a1ccef Mon Sep 17 00:00:00 2001
From: Jim O'Donnell <jim@zooniverse.org>
Date: Fri, 18 Mar 2022 11:32:55 +0000
Subject: [PATCH] Test the useHydratedStore hook

---
 .../src/hooks/useHydratedStore.spec.js        | 102 ++++++++++++++++++
 packages/lib-classifier/src/hooks/useStore.js |   5 +
 2 files changed, 107 insertions(+)
 create mode 100644 packages/lib-classifier/src/hooks/useHydratedStore.spec.js

diff --git a/packages/lib-classifier/src/hooks/useHydratedStore.spec.js b/packages/lib-classifier/src/hooks/useHydratedStore.spec.js
new file mode 100644
index 00000000000..11fb2fe7ea1
--- /dev/null
+++ b/packages/lib-classifier/src/hooks/useHydratedStore.spec.js
@@ -0,0 +1,102 @@
+import { applySnapshot, getSnapshot } from 'mobx-state-tree'
+import React from 'react'
+import { renderHook } from '@testing-library/react-hooks/pure'
+
+import mockStore from '@test/mockStore'
+import RootStore from '@store/RootStore'
+import { cleanStore } from './useStore'
+import { useHydratedStore } from '.'
+
+describe('Hooks > useHydratedStore', function () {
+  describe('without an existing store', function () {
+    let store
+
+    beforeEach(function () {
+      const { authClient, client } = mockStore()
+      const { result } = renderHook(() => useHydratedStore({ authClient, client }, false, 'test-key'))
+      store = result.current
+    })
+
+    afterEach(function () {
+      cleanStore()
+    })
+
+    it('should create a new store', function () {
+      const mockStore = getSnapshot(RootStore.create({}))
+      const snapshot = getSnapshot(store)
+      expect(snapshot).to.deep.equal(mockStore)
+    })
+  })
+
+  describe('with an existing store', function () {
+    let store
+    let newStore
+
+    beforeEach(function () {
+      const { authClient, client } = mockStore()
+      const { result: firstRun } = renderHook(() => useHydratedStore({ authClient, client }, false, 'test-key'))
+      store = firstRun.current
+      const { result: secondRun } = renderHook(() => useHydratedStore({ authClient, client }, false, 'test-key'))
+      newStore = secondRun.current
+    })
+
+    afterEach(function () {
+      cleanStore()
+    })
+
+    it('should use the existing store', function () {
+      expect(newStore).to.deep.equal(store)
+    })
+  })
+
+  describe('with session storage enabled', function () {
+    let store
+
+    beforeEach(async function () {
+      const expectedStore = mockStore()
+      const { authClient, client } = expectedStore
+      const { result, waitForNextUpdate } = renderHook(() => useHydratedStore({ authClient, client }, true, 'test-key'))
+      await waitForNextUpdate()
+      store = result.current
+      const mockSnapshot = getSnapshot(expectedStore)
+      applySnapshot(store.projects, mockSnapshot.projects)
+    })
+
+    afterEach(function () {
+      cleanStore()
+    })
+
+    it('should save snapshots in session storage', function () {
+      const mockSnapshot = window.sessionStorage.getItem('test-key')
+      const snapshot = getSnapshot(store)
+      expect(JSON.stringify(snapshot)).to.equal(mockSnapshot)
+    })
+  })
+
+  describe('with a saved snapshot', function () {
+    let store
+    let mockSnapshot
+
+    beforeEach(async function () {
+      const expectedStore = mockStore()
+      mockSnapshot = getSnapshot(expectedStore)
+      window.sessionStorage.setItem('test-key', JSON.stringify(mockSnapshot))
+
+      const { authClient, client } = expectedStore
+      const { result, waitFor } = renderHook(() => useHydratedStore({ authClient, client }, true, 'test-key'))
+      await waitFor(() => {
+        store = result.current
+        return !!store?.projects
+      })
+    })
+
+    afterEach(function () {
+      cleanStore()
+    })
+
+    it('should load the snapshot into the store', function () {
+      const snapshot = getSnapshot(store)
+      expect(snapshot.projects).to.deep.equal(mockSnapshot.projects)
+    })
+  })
+})
\ No newline at end of file
diff --git a/packages/lib-classifier/src/hooks/useStore.js b/packages/lib-classifier/src/hooks/useStore.js
index 62c1b1c9008..301b12a4f32 100644
--- a/packages/lib-classifier/src/hooks/useStore.js
+++ b/packages/lib-classifier/src/hooks/useStore.js
@@ -22,4 +22,9 @@ function initStore({ authClient, client, initialState }) {
 export default function useStore({ authClient, client, initialState }) {
   const _store = useMemo(() => initStore({ authClient, client, initialState }), [authClient, initialState])
   return _store
+}
+
+// This can be used to reset the global store during tests.
+export function cleanStore() {
+  store = undefined
 }
\ No newline at end of file