Function runTest

tests/integrations/ckeditor-classiceditor.test.tsx:96–135

( createEditor, destroyEditor )

	// Runs a single test case.
	function runTest( createEditor, destroyEditor ) {
		let memoryAfterFirstStart;

		return Promise
			.resolve()
			// Initialize the first editor before measuring the heap size.
			// A cold start may allocate a bit of memory on the module-level.
			.then( createAndDestroy )
			.then( () => {
				return collectMemoryStats().then( mem => {
					memoryAfterFirstStart = mem;
				} );
			} )
			// Run create&destroy multiple times. Helps scaling up the issue.
			.then( createAndDestroy ) // #1
			.then( createAndDestroy ) // #2
			.then( createAndDestroy ) // #3
			.then( createAndDestroy ) // #4
			.then( createAndDestroy ) // #5
			.then( collectMemoryStats )
			.then( memory => {
				const memoryDifference = ( memory as any ).usedJSHeapSize - memoryAfterFirstStart.usedJSHeapSize;
				// While theoretically we should get 0KB when there's no memory leak, in reality,
				// the results we get (when there are no leaks) vary from -500KB to 500KB (depending on which tests are executed).
				// However, when we had memory leaks, memoryDifference was reaching 20MB,
				// so, in order to detect significant memory leaks we can expect that the heap won't grow more than 1MB.
				expect( memoryDifference, 'used heap size should not grow' ).to.be.at.most( 1e6 );
			} );

		function createAndDestroy() {
			return Promise.resolve()
				.then( createEditor )
				.then( destroyEditor )
				.then( () => {
					// Simulate real world rerendering queue. Unmounting of editor is *async* so it'll take a while
					// to unmount existing instance of editor.
					return timeout( 200 );
				} );
		}
	}

	function collectMemoryStats() {
		return new Promise( resolve => {