fix(ui): fixing tests that stopped working with rca 2.0

ui/src/AppBoot.test.js

@@ -2,6 +2,14 @@ import * as Sentry from "@sentry/browser";
 
 import { SettingsElement, SetupSentry, ParseDefaultFilters } from "./AppBoot";
 
+beforeAll(() => {
+  // https://github.com/jamesmfriedman/rmwc/issues/103#issuecomment-360007979
+  Object.defineProperty(window.HTMLElement.prototype, "dataset", {
+    writable: true,
+    value: {}
+  });
+});
+
 afterEach(() => {
   // reset sentry state before each mock, that's the only way to revert
   // Sentry.init() that I found

ui/src/Components/Grid/AlertGrid/AlertGroup/Alert/__snapshots__/index.test.js.snap

@@ -52,6 +52,7 @@ exports[`<Alert /> matches snapshot with showAlertmanagers=false showReceiver=fa
          role=\\"img\\"
          xmlns=\\"http://www.w3.org/2000/svg\\"
          viewbox=\\"0 0 320 512\\"
+         style=\\"width: 0.8rem;\\"
     >
       <path fill=\\"currentColor\\"
             d=\\"M31.3 192h257.3c17.8 0 26.7 21.5 14.1 34.1L174.1 354.8c-7.8 7.8-20.5 7.8-28.3 0L17.2 226.1C4.6 213.5 13.5 192 31.3 192z\\"

ui/src/Components/Grid/UpgradeNeeded/index.test.js

@@ -22,7 +22,9 @@ describe("<UpgradeNeeded />", () => {
   });
 
   it("calls window.location.reload after timer is done", () => {
-    const reloadSpy = jest.spyOn(global.window.location, "reload");
+    const reloadSpy = jest
+      .spyOn(global.window.location, "reload")
+      .mockImplementation(() => {});
     mount(<UpgradeNeeded newVersion="1.2.3" />);
     jest.runOnlyPendingTimers();
     expect(reloadSpy).toBeCalled();

ui/src/ErrorBoundary.test.js

@@ -30,8 +30,12 @@ const MountedFailingComponent = () => {
 
 describe("<ErrorBoundary />", () => {
   it("matches snapshot", () => {
+    const consoleSpy = jest
+      .spyOn(console, "error")
+      .mockImplementation(() => {});
     const tree = MountedFailingComponent();
     expect(toDiffableHtml(tree.html())).toMatchSnapshot();
+    expect(consoleSpy).toHaveBeenCalled();
   });
 
   it("componentDidCatch should catch an error from FailingComponent", () => {

ui/src/setupTests.js

@@ -5,13 +5,13 @@ import Adapter from "enzyme-adapter-react-16";
 Enzyme.configure({ adapter: new Adapter() });
 
 // localStorage is used for Settings store
-require("jest-localstorage-mock");
+import("jest-localstorage-mock");
 
 // favico.js needs canvas
-require("jest-canvas-mock");
+import("jest-canvas-mock");
 
 // used to mock current time since we render moment.fromNow() in some places
-require("jest-date-mock");
+import("jest-date-mock");
 
 // fetch is used in multiple places to interact with Go backend
 // or upstream Alertmanager API