Add TestRenderer.act callback function

[macintoshhelper]

I am...

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Requesting a new feature

Proposal/Feature-request:

Add callback to render function to run code inside TestRenderer.act function.

react-sketchapp/src/buildTree.ts

Lines 96 to 99 in b238e69

	TestRenderer.act(() => {
	// synchronous callback
	renderer = TestRenderer.create(element);
	});

This should allow for Relay data fetching to occur before the component is rendered: https://relay.dev/docs/guides/testing-relay-components/#examples

I’ll work on hacking together a demo for this with a mock GraphQL Relay API; this could be expanded to having a full Relay example in this repo.