[Mock Scheduler] Mimic browser's advanceTime (#17967)
The mock Scheduler that we use in our tests has its own fake timer implementation. The `unstable_advanceTime` method advances the timeline. Currently, a call to `unstable_advanceTime` will also flush any pending expired work. But that's not how it works in the browser: when a timer fires, the corresponding task is added to the Scheduler queue. However, we will still wait until the next message event before flushing it. This commit changes `unstable_advanceTime` to more closely resemble the browser behavior, by removing the automatic flushing of expired work. ```js // Before this commit Scheduler.unstable_advanceTime(ms); // Equivalent behavior after this commit Scheduler.unstable_advanceTime(ms); Scheduler.unstable_flushExpired(); ``` The general principle is to prefer separate APIs for scheduling tasks and flushing them. This change does not affect any public APIs. `unstable_advanceTime` is only used by our own test suite. It is not used by `act`. However, we may need to update tests in www, like Relay's.
Andrew Clark committed
Feb 4, 2020 at 11:35 UTC
9dba218d933d66fba9a8ba23b90dbb852514da8b
5 files changed
+14
-16
packages/react-dom/src/events/__tests__/ChangeEventPlugin-test.internal.js
+1
@@ -779,6 +779,7 @@ describe('ChangeEventPlugin', () => {
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// 3s should be enough to expire the updates
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Scheduler.unstable_advanceTime(3000);
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+ expect(Scheduler).toFlushExpired([]);
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expect(container.textContent).toEqual('hovered');
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});
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},
packages/react-reconciler/src/__tests__/ReactIncrementalUpdates-test.internal.js
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@@ -540,7 +540,7 @@ describe('ReactIncrementalUpdates', () => {
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// All the updates should render and commit in a single batch.
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Scheduler.unstable_advanceTime(10000);
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- expect(Scheduler).toHaveYielded(['Render: goodbye']);
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+ expect(Scheduler).toFlushExpired(['Render: goodbye']);
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// Passive effect
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expect(Scheduler).toFlushAndYield(['Commit: goodbye']);
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});
@@ -645,7 +645,7 @@ describe('ReactIncrementalUpdates', () => {
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// All the updates should render and commit in a single batch.
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Scheduler.unstable_advanceTime(10000);
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- expect(Scheduler).toHaveYielded([
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+ expect(Scheduler).toFlushExpired([
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'Render: goodbye',
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'Commit: goodbye',
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'Render: goodbye',
packages/react-reconciler/src/__tests__/ReactSuspenseWithNoopRenderer-test.internal.js
+2
-2
@@ -848,7 +848,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
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</Suspense>,
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);
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Scheduler.unstable_advanceTime(10000);
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- expect(Scheduler).toHaveYielded([
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+ expect(Scheduler).toFlushExpired([
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'Suspend! [A]',
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'Suspend! [B]',
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'Loading...',
@@ -987,7 +987,7 @@ describe('ReactSuspenseWithNoopRenderer', () => {
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Scheduler.unstable_advanceTime(10000);
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jest.advanceTimersByTime(10000);
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- expect(Scheduler).toHaveYielded([
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+ expect(Scheduler).toFlushExpired([
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'Suspend! [goodbye]',
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'Loading...',
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'Commit: goodbye',
packages/scheduler/src/__tests__/Scheduler-test.js
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-5
@@ -117,14 +117,14 @@ describe('Scheduler', () => {
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// Advance by just a bit more to expire the user blocking callbacks
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Scheduler.unstable_advanceTime(1);
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- expect(Scheduler).toHaveYielded([
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+ expect(Scheduler).toFlushExpired([
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'B (did timeout: true)',
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'C (did timeout: true)',
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]);
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// Expire A
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Scheduler.unstable_advanceTime(4600);
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- expect(Scheduler).toHaveYielded(['A (did timeout: true)']);
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+ expect(Scheduler).toFlushExpired(['A (did timeout: true)']);
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// Flush the rest without expiring
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expect(Scheduler).toFlushAndYield([
@@ -140,7 +140,7 @@ describe('Scheduler', () => {
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expect(Scheduler).toHaveYielded([]);
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Scheduler.unstable_advanceTime(1);
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- expect(Scheduler).toHaveYielded(['A']);
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+ expect(Scheduler).toFlushExpired(['A']);
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});
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it('continues working on same task after yielding', () => {
@@ -217,7 +217,7 @@ describe('Scheduler', () => {
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// Advance time by just a bit more. This should expire all the remaining work.
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Scheduler.unstable_advanceTime(1);
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- expect(Scheduler).toHaveYielded(['C', 'D']);
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+ expect(Scheduler).toFlushExpired(['C', 'D']);
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});
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it('continuations are interrupted by higher priority work', () => {
@@ -705,7 +705,7 @@ describe('Scheduler', () => {
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// Now it expires
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Scheduler.unstable_advanceTime(1);
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- expect(Scheduler).toHaveYielded(['A']);
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+ expect(Scheduler).toFlushExpired(['A']);
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});
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it('cancels a delayed task', () => {
packages/scheduler/src/forks/SchedulerHostConfig.mock.js
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-7
@@ -201,13 +201,10 @@ export function unstable_yieldValue(value: mixed): void {
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export function unstable_advanceTime(ms: number) {
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currentTime += ms;
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- if (!isFlushing) {
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- if (scheduledTimeout !== null && timeoutTime <= currentTime) {
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- scheduledTimeout(currentTime);
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- timeoutTime = -1;
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- scheduledTimeout = null;
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- }
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- unstable_flushExpired();
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+ if (scheduledTimeout !== null && timeoutTime <= currentTime) {
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+ scheduledTimeout(currentTime);
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+ timeoutTime = -1;
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+ scheduledTimeout = null;
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}
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}
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