test(test-utils): Add MemoryProfiler for heap snapshot testing via CDP#20555
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test(test-utils): Add MemoryProfiler for heap snapshot testing via CDP#20555
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s1gr1d
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| private async _collectGarbage(): Promise<void> { | ||
| // Multiple GC passes to ensure full collection - some V8 inspectors need this | ||
| for (let i = 0; i < 3; i++) { |
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There are different steps in GCing. Usually one is enough, but I wanted to make sure that everything is really garbage collected and therefore only leaks are getting tested:
For that purpose, multiple rounds of work and additional tweaks to the garbage collection process may be needed since some steps (e.g. invocation of weak callbacks) are not designed to be run immediately.
(https://joyeecheung.github.io/blog/2023/12/30/fixing-nodejs-vm-apis-3/)
| let totalSize = 0; | ||
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| if (selfSizeIdx !== -1) { | ||
| for (let i = 0; i < snapshot.nodes.length; i += nodeFieldCount) { |
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You could use a for of here as you are iterating over the nodes
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Don't think that would work as I don't step directly over snapshot.nodes and don't increment i by one with i++ but with i += nodeFieldCount
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whoops, should have read more closely
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chargome
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May 4, 2026
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Looks like a useful improvement!
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| export interface HeapUsage { | ||
| usedSize: number; | ||
| totalSize: number; | ||
| } |
| edgeGrowth, | ||
| edgeGrowthPercent: (edgeGrowth / baseline.edgeCount) * 100, | ||
| sizeGrowth, | ||
| sizeGrowthPercent: (sizeGrowth / baseline.totalSize) * 100, |
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l: Already flagged by the clankers, but we could just do | 1?
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Changed it to result in 0 instead
s1gr1d
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Adds CDPClient and MemoryProfiler to test-utils for V8 heap profiling. This PR prevents #20407 entirely by comparing heap snapshots.
Within a Playwright test following can now be used:
This works by using the Chrome Developer Protocol (CDP). There is also a CDPSession API available from Playwright, but that would only work for sessions which run in the browser. Theoretically, this could also work in integration tests, but the idea is that this could in the future also be extended to use the CDPSession from Playwright for browser tests.