Add offline fixture-based testing framework

[Copilot]

Edupage has no REST API, so the library parses HTML/JS responses that can change without notice. There's currently no way to test parsing logic without live credentials and a real Edupage session.

New module: edupage_api/testing.py

• EduRecorder — context manager that wraps session.send to intercept a live session and serialise every HTTP exchange plus edupage.data to a JSON fixture file. Accepts an optional anonymiser callback to scrub personal data before writing.
• MockSession — requests.Session subclass that replays responses from a fixture keyed by (method, url). Raises UnexpectedRequestError for any unmapped request, keeping tests deterministic. Multiple responses for the same URL are consumed in order.
• EdupageTestCase — unittest.TestCase base class with a get_edupage(fixture_path) factory that hydrates a fresh Edupage instance from a fixture and swaps in MockSession — no login flow, no network.

Fixture format

{
  "meta": { "subdomain": "myschool", "username": "student", "gsec_hash": "…" },
  "data": { /* full userhome payload */ },
  "requests": [
    {
      "method": "GET",
      "url": "https://myschool.edupage.org/znamky/",
      "response": { "status_code": 200, "text": "…" }
    }
  ]
}

Multiple fixture variants per feature (grades_school_a.json, grades_school_b.json) let you assert that parsers handle both old and new server response shapes simultaneously.

Usage

Record once (requires a real account):

from edupage_api import Edupage
from edupage_api.testing import EduRecorder

edupage = Edupage()
with EduRecorder(edupage, "tests/fixtures/grades.json", anonymiser=scrub):
    edupage.login("user", "pass", "myschool")
    edupage.get_grades()

Replay in CI (no credentials):

from edupage_api.testing import EdupageTestCase

class GradesTest(EdupageTestCase):
    def test_grade_count(self):
        edupage = self.get_edupage("tests/fixtures/grades.json")
        self.assertEqual(len(edupage.get_grades()), 5)

Initial tests

Adds tests/fixtures/notifications.json (synthetic, anonymised) and tests/test_notifications.py (19 tests) covering timeline item parsing, userProps state (starred/done), and MockSession error behaviour — all without network access.