Fix tests requiring a js dom environment

[ChristophWurst]

https://jestjs.io/docs/configuration#testenvironment-string

Tests can't be run otherwise.

 FAIL  test/scopedstorage.test.js
  ● ScopedStorage › sets an item

    The error below may be caused by using the wrong test environment, see https://jestjs.io/docs/configuration#testenvironment-string.
    Consider using the "jsdom" test environment.
    
    ReferenceError: window is not defined

      10 |
      11 |     beforeEach(() => {
    > 12 |         wrapped = window.localStorage
         |         ^
      13 |         storage = new ScopedStorage('test', wrapped, false)
      14 |     })
      15 |

      at Object.<anonymous> (test/scopedstorage.test.js:12:9)

[tcitworld]

Since every test uses this, you might as well add some jest config file with testEnvironment: 'jsdom' instead?