refactor(router): a Navigator adapter as the seam

shared/chat/inbox/reselect-conversation.test.ts

@@ -1,22 +1,16 @@
 /// <reference types="jest" />
 import * as T from '@/constants/types'
+import * as Tabs from '@/constants/tabs'
 import {resetAllStores} from '@/util/zustand'
 import {useConfigState} from '@/stores/config'
 
-jest.mock('@/constants/router', () => ({
-  getModalStack: jest.fn(() => []),
-  getVisibleScreen: jest.fn(() => undefined),
-  navigateToInbox: jest.fn(),
-  navigateToThread: jest.fn(),
-}))
-
 jest.mock('@/constants/chat/common', () => ({
   ...jest.requireActual('@/constants/chat/common'),
   getSelectedConversation: jest.fn(),
 }))
 
 import * as Common from '@/constants/chat/common'
-import {navigateToInbox, navigateToThread} from '@/constants/router'
+import {installFakeNavigator, makeRootState, restoreNavigator, type FakeNavigator} from '@/test/fake-navigator'
 import {maybeChangeSelectedConversation} from './metadata'
 
 const newConvID = 'ff00ff00'
@@ -25,12 +19,21 @@ const mockedSelected = Common.getSelectedConversation as jest.Mock
 const layout = (over: Partial<T.RPCChat.UIInboxReselectInfo>): T.RPCChat.UIInboxLayout =>
   ({reselectInfo: {oldConvID: '', ...over}}) as T.RPCChat.UIInboxLayout
 
+let nav: FakeNavigator
+
+// navigateToInbox defers a tick, so every assertion below has to let that tick run.
+const runDeferredNavigation = () => jest.advanceTimersByTime(1)
+
 beforeEach(() => {
+  jest.useFakeTimers()
+  nav = installFakeNavigator()
   useConfigState.setState({loggedIn: true})
   global.isMobile = true
 })
 
 afterEach(() => {
+  restoreNavigator()
+  jest.useRealTimers()
   jest.clearAllMocks()
   resetAllStores()
   global.isMobile = false
@@ -45,16 +48,17 @@ test('a reselect while a conversation creation is pending does not pop to the in
 
   maybeChangeSelectedConversation(layout({newConvID}))
 
-  expect(navigateToInbox).not.toHaveBeenCalled()
-  expect(navigateToThread).not.toHaveBeenCalled()
+  runDeferredNavigation()
+  expect(nav.actions).toEqual([])
 })
 
 test('a reselect while the create error screen is up does not pop to the inbox', () => {
   mockedSelected.mockReturnValue(T.Chat.pendingErrorConversationIDKey)
 
   maybeChangeSelectedConversation(layout({newConvID}))
 
-  expect(navigateToInbox).not.toHaveBeenCalled()
+  runDeferredNavigation()
+  expect(nav.actions).toEqual([])
 })
 
 // the real "we are on a dead conversation" case still has to bounce
@@ -63,5 +67,20 @@ test('a reselect with nothing selected still goes to the inbox on mobile', () =>
 
   maybeChangeSelectedConversation(layout({newConvID}))
 
-  expect(navigateToInbox).toHaveBeenCalledWith(false)
+  runDeferredNavigation()
+  // navigateToInbox(false): stay on the chat tab and pop its stack back to the inbox
+  expect(nav.types()).toContain('POP_TO')
+  expect(nav.lastAction()?.payload).toMatchObject({name: 'chatRoot'})
+})
+
+// The bounce is navigateToInbox(false): it must not pull the user off whatever tab they
+// are on. Only the chat tab's own stack gets popped.
+test('a reselect while another tab is up leaves that tab alone', () => {
+  nav = installFakeNavigator({rootState: makeRootState({tab: Tabs.teamsTab})})
+  mockedSelected.mockReturnValue(T.Chat.noConversationIDKey)
+
+  maybeChangeSelectedConversation(layout({newConvID}))
+
+  runDeferredNavigation()
+  expect(nav.actions).toEqual([])
 })

shared/common-adapters/name-with-icon.test.tsx

@@ -17,7 +17,6 @@ jest.mock('@/stores/followers', () => ({
   },
 }))
 jest.mock('@/teams/use-teams-list', () => ({useTeamsListNameToIDMap: () => new Map<string, string>()}))
-jest.mock('@/constants/router', () => ({navToProfile: jest.fn()}))
 jest.mock('./avatar', () => ({
   __esModule: true,
   default: ({
@@ -73,17 +72,22 @@ jest.mock('./text', () => ({
     require('react').createElement('span', null, children),
 }))
 
+import {installFakeNavigator, restoreNavigator, type FakeNavigator} from '@/test/fake-navigator'
 import {NameWithIcon} from './name-with-icon'
 
 const avatar = () => screen.queryByTestId('avatar')
 const followIcon = () => screen.queryByTestId('follow-icon')
 
+let nav: FakeNavigator
+
 describe('NameWithIcon', () => {
   beforeEach(() => {
     mockFollowerReads.length = 0
+    nav = installFakeNavigator()
   })
   afterEach(() => {
     cleanup()
+    restoreNavigator()
     mockFollowers.followers = new Set()
     mockFollowers.following = new Set()
   })
@@ -209,6 +213,7 @@ describe('NameWithIcon', () => {
       render(<NameWithIcon username="testuser" onClick={onClick} />)
       screen.getByTestId('clickable').click()
       expect(onClick).toHaveBeenCalledWith('testuser')
+      expect(nav.actions).toEqual([])
     })
 
     test('no onClick means no clickable wrapper', () => {

shared/constants/nav-debug.tsx

@@ -0,0 +1,3 @@
+// Flip to log every navigation the router makes. Its own module so that the router store
+// can read it without depending on the navigation adapter.
+export const DEBUG_NAV = __DEV__ && (false as boolean)

shared/constants/nav-tree.tsx

@@ -60,6 +60,14 @@ let modalRouteNames: ReadonlySet<string> | undefined
 export const setModalRouteNames = (names: Iterable<string>) => {
   modalRouteNames = new Set<string>(names)
 }
+// For tests that register their own: returns a function that puts back the registration as
+// it is now, including "not registered".
+export const saveModalRouteNames = () => {
+  const saved = modalRouteNames
+  return () => {
+    modalRouteNames = saved
+  }
+}
 export const isModalRouteName = (name: string) => {
   if (!modalRouteNames) {
     throw new Error('modalRouteNames not registered; call setModalRouteNames at startup')

shared/constants/navigate-append-once-root-has.test.ts

@@ -42,8 +42,9 @@ afterEach(() => {
   jest.restoreAllMocks()
 })
 
-// Each test pushes distinct params: navigateAppend's module-private `_pendingAppend` dupe cache
-// would otherwise swallow a same-shaped push from an earlier test.
+// These drive the real container adapter, whose Navigator lives for the whole file. Each test
+// pushes distinct params: its in-flight dupe check would otherwise swallow a same-shaped push
+// from an earlier test.
 const pushOf = (username: string) =>
   expect.objectContaining({payload: {name: 'username', params: {username}}, type: 'PUSH'})