def test_reserve_seat_when_already_reserved():
service = TrainDataService("""{ "foo_train": {"seats": {"1A": {"coach": "A", "seat_number": "1", "booking_reference": "existing"} }}}""")
response = service.reserve("foo_train", json.dumps(["1A"]), "01234567")
assert "already booked with reference: existing" in response
train_data = service.data_for_train("foo_train")
assert '"booking_reference": "existing"' in train_data
def test_fetch_train_data():
service = TrainDataService("""{ "foo_train": {"seats": {"1A": {"coach": "A", "seat_number": "1", "booking_reference": ""} }}}""")
train_data = service.data_for_train("foo_train")
assert "1A" in train_data
def test_reserve_seat():
service = TrainDataService("""{ "foo_train": {"seats": {"1A": {"coach": "A", "seat_number": "1", "booking_reference": ""} }}}""")
service.reserve("foo_train", json.dumps(["1A"]), "01234567")
train_data = service.data_for_train("foo_train")
assert '"booking_reference": "01234567"' in train_data
