src/vs/workbench/services/extensions/common/abstractExtensionService.ts/AbstractExtensionService/_handleExtensionTests
class AbstractExtensionService:	private async _handleExtensionTests(): Promise<void> {
		if (!this._environmentService.isExtensionDevelopment || !this._environmentService.extensionTestsLocationURI) {
			return;
		}

		const extensionHostManager = this.findTestExtensionHost(this._environmentService.extensionTestsLocationURI);
		if (!extensionHostManager) {
			const msg = nls.localize('extensionTestError', "No extension host found that can launch the test runner at {0}.", this._environmentService.extensionTestsLocationURI.toString());
			console.error(msg);
			this._notificationService.error(msg);
			return;
		}


		let exitCode: number;
		try {
			exitCode = await extensionHostManager.extensionTestsExecute();
		} catch (err) {
			console.error(err);
			exitCode = 1 /* ERROR */;
		}

		this._onExtensionHostExit(exitCode);
	}