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test(svelte-query-persist-client/PersistQueryClientProvider): switch to fake timers, replace 'waitFor' with 'advanceTimersByTimeAsync', and use 'sleep().then()' pattern#9900

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Merged
TkDodo merged 4 commits into from
Dec 27, 2025
Merged

test(svelte-query-persist-client/PersistQueryClientProvider): switch to fake timers, replace 'waitFor' with 'advanceTimersByTimeAsync', and use 'sleep().then()' pattern #9900

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830acac
test(svelte-query-persist-client/PersistQueryClientProvider): switch …
sukvvon Nov 23, 2025
163797c
test(svelte-query-persist-client/PersistQueryClientProvider): replace…
sukvvon Nov 26, 2025
c38c8e7
refactor(svelte-query-persist-client/FreshData): convert complex 'the…
sukvvon Dec 17, 2025
89b5f0c
Merge branch 'main' into test/svelte-query-persist-client-fake-timers
sukvvon Dec 19, 2025
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2 changes: 1 addition & 1 deletion packages/svelte-query-persist-client/tests/AwaitOnSuccess/AwaitOnSuccess.svelte
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Original file line numberDiff line numberDiff line change
Expand Up@@ -9,7 +9,7 @@
queryKey: ['test'],
queryFn: async () => {
states.current.push('fetching')
await sleep(5)
await sleep(10)
states.current.push('fetched')
return 'fetched'
},
Expand Down
12 changes: 9 additions & 3 deletions packages/svelte-query-persist-client/tests/FreshData/FreshData.svelte
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Original file line numberDiff line numberDiff line change
@@ -1,17 +1,23 @@
<script lang="ts">
import { createQuery } from '@tanstack/svelte-query'
import { sleep } from '@tanstack/query-test-utils'
import type { StatelessRef, StatusResult } from '../utils.svelte.js'

let {
states,
onFetch,
}: {
states: StatelessRef<Array<StatusResult<string>>>
onFetch: () => void
} = $props()

const query = createQuery(() => ({
queryKey: ['test'],
queryFn: () => Promise.resolve('fetched'),

queryFn: async () => {
await sleep(10)
onFetch()
return 'fetched'
},
staleTime: Infinity,
}))

Expand All@@ -22,5 +28,5 @@
})
</script>

<div>data: {query.data ?? 'undefined'}</div>
<div>data: {query.data ?? 'null'}</div>
<div>fetchStatus: {query.fetchStatus}</div>
5 changes: 3 additions & 2 deletions packages/svelte-query-persist-client/tests/FreshData/Provider.svelte
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Expand Up@@ -9,11 +9,12 @@
queryClient: QueryClient
persistOptions: OmitKeyof<PersistQueryClientOptions, 'queryClient'>
states: StatelessRef<Array<StatusResult<string>>>
onFetch: () => void
}

let { queryClient, persistOptions, states }: Props = $props()
let { queryClient, persistOptions, states, onFetch }: Props = $props()
</script>

<PersistQueryClientProvider client={queryClient} {persistOptions}>
<FreshData {states} />
<FreshData {states} {onFetch} />
</PersistQueryClientProvider>
6 changes: 1 addition & 5 deletions packages/svelte-query-persist-client/tests/InitialData/InitialData.svelte
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Expand Up@@ -8,11 +8,7 @@

const query = createQuery(() => ({
queryKey: ['test'],
queryFn: async () => {
await sleep(5)
return 'fetched'
},

queryFn: () => sleep(10).then(() => 'fetched'),

@TkDodoTkDodoNov 25, 2025

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why is this better than await ?

@sukvvonsukvvonNov 26, 2025

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@TkDodo

In my opinion, sleep().then() is more concise than async/await. There's no functional difference, but it avoids the async keyword and extra braces, and makes the timer-to-callback dependency explicit in a single line. I discussed this with @manudeli.

// await: 4 linesasync()=>{awaitsleep(10)return'fetched'}// then: 1 line()=>sleep(10).then(()=>'fetched')

@TkDodoTkDodoNov 26, 2025

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okay but we have over 350 instances of await sleep(...) and I think it’s unnecessary to refactor them “just because”. This is also only true if you have a single await statement, we also sometimes have:

mutationFn: async () => {
results.push('start-A')
await sleep(10)
results.push('finish-A')
return 'a'
}

which is much more readable with async/await.

If it’s all the same, I’d like to keep it as-is.

@sukvvonsukvvonNov 26, 2025•
edited
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So the .then() ones from the fake timers PRs that already got merged stay put, use .then() for single-statement cases as I suggested, and keep await otherwise from now on?

@TkDodoTkDodoDec 27, 2025

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we don’t have a lint rule for this so I don’t really care but I don’t see the value in re-writing a pattern like this in our tests. We now have a mixture of both usages anyways 🤷‍♂️

initialData: 'initial',
// make sure that initial data is older than the hydration data
// otherwise initialData would be newer and takes precedence
Expand Down
3 changes: 2 additions & 1 deletion packages/svelte-query-persist-client/tests/OnSuccess/OnSuccess.svelte
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Original file line numberDiff line numberDiff line change
@@ -1,9 +1,10 @@
<script lang="ts">
import { createQuery } from '@tanstack/svelte-query'
import { sleep } from '@tanstack/query-test-utils'

const query = createQuery(() => ({
queryKey: ['test'],
queryFn: () => Promise.resolve('fetched'),
queryFn: () => sleep(10).then(() => 'fetched'),
}))
</script>

Expand Down
123 changes: 80 additions & 43 deletions packages/svelte-query-persist-client/tests/PersistQueryClientProvider.svelte.test.ts
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Original file line numberDiff line numberDiff line change
@@ -1,5 +1,5 @@
import { render, waitFor } from '@testing-library/svelte'
import { describe, expect, test, vi } from 'vitest'
import { render } from '@testing-library/svelte'
import { afterEach, beforeEach, describe, expect, test, vi } from 'vitest'
import { QueryClient } from '@tanstack/svelte-query'
import { persistQueryClientSave } from '@tanstack/query-persist-client-core'
import { sleep } from '@tanstack/query-test-utils'
Expand All@@ -17,6 +17,14 @@ import type {
} from '@tanstack/query-persist-client-core'
import type { StatusResult } from './utils.svelte.js'

beforeEach(() => {
vi.useFakeTimers()
})

afterEach(() => {
vi.useRealTimers()
})

const createMockPersister = (): Persister => {
let storedState: PersistedClient | undefined

Expand All@@ -25,7 +33,7 @@ const createMockPersister = (): Persister => {
storedState = persistClient
},
async restoreClient() {
return Promise.resolve(storedState)
return sleep(10).then(() => storedState)
},
removeClient() {
storedState = undefined
Expand All@@ -44,7 +52,7 @@ const createMockErrorPersister = (
// noop
},
async restoreClient() {
return Promise.reject(error)
return sleep(10).then(() => Promise.reject(error))
},
removeClient,
},
Expand All@@ -56,14 +64,16 @@ describe('PersistQueryClientProvider', () => {
const states = new StatelessRef<Array<StatusResult<string>>>([])

const queryClient = new QueryClient()
await queryClient.prefetchQuery({
queryClient.prefetchQuery({
queryKey: ['test'],
queryFn: () => Promise.resolve('hydrated'),
queryFn: () => sleep(10).then(() => 'hydrated'),
})
await vi.advanceTimersByTimeAsync(10)

const persister = createMockPersister()

await persistQueryClientSave({ queryClient, persister })
persistQueryClientSave({ queryClient, persister })
await vi.advanceTimersByTimeAsync(0)

queryClient.clear()

Expand All@@ -75,9 +85,11 @@ describe('PersistQueryClientProvider', () => {
},
})

await waitFor(() => rendered.getByText('fetchStatus: idle'))
await waitFor(() => rendered.getByText('hydrated'))
await waitFor(() => rendered.getByText('fetched'))
expect(rendered.getByText('fetchStatus: idle')).toBeInTheDocument()
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('hydrated')).toBeInTheDocument()
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('fetched')).toBeInTheDocument()

expect(states.current).toHaveLength(3)

Expand All@@ -104,14 +116,16 @@ describe('PersistQueryClientProvider', () => {
const states = new StatelessRef<Array<StatusResult<string>>>([])

const queryClient = new QueryClient()
await queryClient.prefetchQuery({
queryClient.prefetchQuery({
queryKey: ['test'],
queryFn: () => Promise.resolve('hydrated'),
queryFn: () => sleep(10).then(() => 'hydrated'),
})
await vi.advanceTimersByTimeAsync(10)

const persister = createMockPersister()

await persistQueryClientSave({ queryClient, persister })
persistQueryClientSave({ queryClient, persister })
await vi.advanceTimersByTimeAsync(0)

queryClient.clear()

Expand All@@ -123,9 +137,11 @@ describe('PersistQueryClientProvider', () => {
},
})

await waitFor(() => rendered.getByText('fetchStatus: idle'))
await waitFor(() => rendered.getByText('hydrated'))
await waitFor(() => rendered.getByText('fetched'))
expect(rendered.getByText('fetchStatus: idle')).toBeInTheDocument()
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('hydrated')).toBeInTheDocument()
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('fetched')).toBeInTheDocument()

expect(states.current).toHaveLength(3)

Expand All@@ -152,14 +168,16 @@ describe('PersistQueryClientProvider', () => {
const states = new StatelessRef<Array<StatusResult<string>>>([])

const queryClient = new QueryClient()
await queryClient.prefetchQuery({
queryClient.prefetchQuery({
queryKey: ['test'],
queryFn: () => Promise.resolve('hydrated'),
queryFn: () => sleep(10).then(() => 'hydrated'),
})
await vi.advanceTimersByTimeAsync(10)

const persister = createMockPersister()

await persistQueryClientSave({ queryClient, persister })
persistQueryClientSave({ queryClient, persister })
await vi.advanceTimersByTimeAsync(0)

queryClient.clear()

Expand All@@ -171,9 +189,11 @@ describe('PersistQueryClientProvider', () => {
},
})

await waitFor(() => rendered.getByText('initial'))
await waitFor(() => rendered.getByText('hydrated'))
await waitFor(() => rendered.getByText('fetched'))
expect(rendered.getByText('initial')).toBeInTheDocument()
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('hydrated')).toBeInTheDocument()
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('fetched')).toBeInTheDocument()

expect(states.current).toHaveLength(3)

Expand All@@ -200,35 +220,42 @@ describe('PersistQueryClientProvider', () => {
const states = new StatelessRef<Array<StatusResult<string>>>([])

const queryClient = new QueryClient()
await queryClient.prefetchQuery({
queryClient.prefetchQuery({
queryKey: ['test'],
queryFn: () => Promise.resolve('hydrated'),
queryFn: () => sleep(10).then(() => 'hydrated'),
})
await vi.advanceTimersByTimeAsync(10)

const persister = createMockPersister()

await persistQueryClientSave({ queryClient, persister })
persistQueryClientSave({ queryClient, persister })
await vi.advanceTimersByTimeAsync(0)

queryClient.clear()

let fetched = false

const rendered = render(FreshData, {
props: {
queryClient,
persistOptions: { persister },
states,
onFetch: () => {
fetched = true
},
},
})

await waitFor(() => rendered.getByText('data: undefined'))
await waitFor(() => rendered.getByText('data: hydrated'))
await expect(
waitFor(() => rendered.getByText('data: fetched'), {
timeout: 100,
}),
).rejects.toThrowError()
expect(rendered.getByText('data: null')).toBeInTheDocument()
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('data: hydrated')).toBeInTheDocument()
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('data: hydrated')).toBeInTheDocument()

expect(states.current).toHaveLength(2)

expect(fetched).toBe(false)

expect(states.current[0]).toMatchObject({
status: 'pending',
fetchStatus: 'idle',
Expand All@@ -244,14 +271,16 @@ describe('PersistQueryClientProvider', () => {

test('should call onSuccess after successful restoring', async () => {
const queryClient = new QueryClient()
await queryClient.prefetchQuery({
queryClient.prefetchQuery({
queryKey: ['test'],
queryFn: () => Promise.resolve('hydrated'),
queryFn: () => sleep(10).then(() => 'hydrated'),
})
await vi.advanceTimersByTimeAsync(10)

const persister = createMockPersister()

await persistQueryClientSave({ queryClient, persister })
persistQueryClientSave({ queryClient, persister })
await vi.advanceTimersByTimeAsync(0)

queryClient.clear()

Expand All@@ -266,21 +295,25 @@ describe('PersistQueryClientProvider', () => {
})

expect(onSuccess).toHaveBeenCalledTimes(0)
await waitFor(() => rendered.getByText('hydrated'))
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('hydrated')).toBeInTheDocument()
expect(onSuccess).toHaveBeenCalledTimes(1)
await waitFor(() => rendered.getByText('fetched'))
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('fetched')).toBeInTheDocument()
})

test('should await onSuccess after successful restoring', async () => {
const queryClient = new QueryClient()
await queryClient.prefetchQuery({
queryClient.prefetchQuery({
queryKey: ['test'],
queryFn: () => Promise.resolve('hydrated'),
queryFn: () => sleep(10).then(() => 'hydrated'),
})
await vi.advanceTimersByTimeAsync(10)

const persister = createMockPersister()

await persistQueryClientSave({ queryClient, persister })
persistQueryClientSave({ queryClient, persister })
await vi.advanceTimersByTimeAsync(0)

queryClient.clear()

Expand All@@ -299,8 +332,10 @@ describe('PersistQueryClientProvider', () => {
},
})

await waitFor(() => rendered.getByText('hydrated'))
await waitFor(() => rendered.getByText('fetched'))
await vi.advanceTimersByTimeAsync(15)
expect(rendered.getByText('hydrated')).toBeInTheDocument()
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('fetched')).toBeInTheDocument()

expect(states.current).toEqual([
'onSuccess',
Expand DownExpand Up@@ -329,7 +364,9 @@ describe('PersistQueryClientProvider', () => {
props: { queryClient, persistOptions: { persister }, onError, onSuccess },
})

await waitFor(() => rendered.getByText('fetched'))
await vi.advanceTimersByTimeAsync(10)
await vi.advanceTimersByTimeAsync(10)
expect(rendered.getByText('fetched')).toBeInTheDocument()
expect(removeClient).toHaveBeenCalledTimes(1)
expect(onSuccess).toHaveBeenCalledTimes(0)
expect(onError).toHaveBeenCalledTimes(1)
Expand Down
3 changes: 2 additions & 1 deletion packages/svelte-query-persist-client/tests/RemoveCache/RemoveCache.svelte
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@@ -1,9 +1,10 @@
<script lang="ts">
import { createQuery } from '@tanstack/svelte-query'
import { sleep } from '@tanstack/query-test-utils'

const query = createQuery(() => ({
queryKey: ['test'],
queryFn: () => Promise.resolve('fetched'),
queryFn: () => sleep(10).then(() => 'fetched'),
}))
</script>

Expand Down
3 changes: 2 additions & 1 deletion packages/svelte-query-persist-client/tests/RestoreCache/RestoreCache.svelte
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@@ -1,13 +1,14 @@
<script lang="ts">
import { createQuery } from '@tanstack/svelte-query'
import { sleep } from '@tanstack/query-test-utils'
import type { StatelessRef, StatusResult } from '../utils.svelte.js'

let { states }: { states: StatelessRef<Array<StatusResult<string>>> } =
$props()

const query = createQuery(() => ({
queryKey: ['test'],
queryFn: async () => Promise.resolve('fetched'),
queryFn: () => sleep(10).then(() => 'fetched'),
}))

$effect(() => {
Expand Down
3 changes: 2 additions & 1 deletion packages/svelte-query-persist-client/tests/UseQueries/UseQueries.svelte
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Original file line numberDiff line numberDiff line change
@@ -1,5 +1,6 @@
<script lang="ts">
import { createQueries } from '@tanstack/svelte-query'
import { sleep } from '@tanstack/query-test-utils'
import type { StatelessRef, StatusResult } from '../utils.svelte.js'

let { states }: { states: StatelessRef<Array<StatusResult<string>>> } =
Expand All@@ -9,7 +10,7 @@
queries: [
{
queryKey: ['test'],
queryFn: () => Promise.resolve('fetched'),
queryFn: () => sleep(10).then(() => 'fetched'),
},
],
}))
Expand Down
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