tests fixed (ref. #31)

__tests__/service-worker.test.js

@@ -377,6 +377,7 @@ describe("service-worker", () => {
     // event.waitUntil() in the install event handler is not handled correctly in NodeJS
     await new Promise(resolve => resolve(true))
     await self.trigger('activate')
+    await new Promise(resolve => resolve(true))
     expect(typeof self.LibResilientConfig).toEqual('object')
     expect(self.LibResilientConfig.defaultPluginTimeout).toBe(5000)
     expect(self.LibResilientConfig.plugins).toStrictEqual([{name: "cache"}])