Test suite is failing locally

Hello, I would like to contribute to the repository, but I found that some tests in the tests suite are failing when running locally.

- in Firefox, when opening `tests/index.html`, there is a failure in one of `socket feature` tests
- in Chrome, in `tests/index.html`, all `cookies` tests are failing, and the `sockets` test as well (4 in total)
- when running in CLI through `npm test`, 11 tests are failing

```
1) _hyperscript bootstrapping
"before each" hook for "on a single div":
TypeError: Cannot set properties of null (setting 'innerHTML')
at clearWorkArea (util/util.js:58:26)
at Context. (core/bootstrap.js:3:3)

2) _hyperscript bootstrapping
"after each" hook for "on a single div":
TypeError: Cannot set properties of null (setting 'innerHTML')
at clearWorkArea (util/util.js:58:26)
at Context. (core/bootstrap.js:6:3)

3) the on feature
can queue events:
Uncaught Error: Script error. (:0)

4) the on feature
can queue events:
Error: global leak(s) detected: 'increment'

5) the on feature
async exceptions don't kill the event queue:
Uncaught Error: Script error. (:0)

6) the worker feature
can define a basic no arg function in a worker:
Error: Timeout of 2000ms exceeded. For async tests and hooks, ensure "done()" is called; if returning a Promise, ensure it resolves.

7) the worker feature
can define a basic no arg function in a worker:
Error: global leak(s) detected: 'example'

8) the socket feature
can handle different url schemes:
AssertionError: No scheme: Should not have thrown
at Context. (features/socket.js:27:12)

9) the cookies identifier
basic set cookie values work:
TypeError: Cannot read properties of undefined (reading 'should')
at Context. (expressions/cookies.js:15:10)

10) the cookies identifier
update cookie values work:
TypeError: Cannot read properties of undefined (reading 'should')
at Context. (expressions/cookies.js:21:10)

11) the cookies identifier
iterate cookies values work:

AssertionError: expected false to equal true
+ expected - actual

-false
+true

at Context. (expressions/cookies.js:38:37)
```

Am I doing anything wrong? What is the correct way of testing hyperscript locally?