self.check_post(form_data, '/day', 400)
self.check_post(form_data, '/day?date=foo', 400)
self.check_post(form_data, '/day?date=2024-01-01', 302)
self.check_post(form_data, '/day', 400)
self.check_post(form_data, '/day?date=foo', 400)
self.check_post(form_data, '/day?date=2024-01-01', 302)