Moves appointment to common and creates serialize

Appointment serialization used to be part of the cryptographer (signature_format) but it makes more sense to be an appointment method. Therefore cli also need Appointment

Also fixes comments based on reviews

test/common/unit/test_appointment.py

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+import json
+from pytest import fixture
+
+from pisa import c_logger
+from common.appointment import Appointment
+from pisa.encrypted_blob import EncryptedBlob
+
+from test.pisa.unit.conftest import get_random_value_hex
+
+from common.constants import LOCATOR_LEN_BYTES
+
+
+c_logger.disabled = True
+
+
+# Not much to test here, adding it for completeness
+@fixture
+def appointment_data():
+    locator = get_random_value_hex(LOCATOR_LEN_BYTES)
+    start_time = 100
+    end_time = 120
+    to_self_delay = 20
+    encrypted_blob_data = get_random_value_hex(100)
+
+    return {
+        "locator": locator,
+        "start_time": start_time,
+        "end_time": end_time,
+        "to_self_delay": to_self_delay,
+        "encrypted_blob": encrypted_blob_data,
+    }
+
+
+def test_init_appointment(appointment_data):
+    # The appointment has no checks whatsoever, since the inspector is the one taking care or that, and the only one
+    # creating appointments.
+    # DISCUSS: whether this makes sense by design or checks should be ported from the inspector to the appointment
+    #          35-appointment-checks
+    appointment = Appointment(
+        appointment_data["locator"],
+        appointment_data["start_time"],
+        appointment_data["end_time"],
+        appointment_data["to_self_delay"],
+        appointment_data["encrypted_blob"],
+    )
+
+    assert (
+        appointment_data["locator"] == appointment.locator
+        and appointment_data["start_time"] == appointment.start_time
+        and appointment_data["end_time"] == appointment.end_time
+        and appointment_data["to_self_delay"] == appointment.to_self_delay
+        and EncryptedBlob(appointment_data["encrypted_blob"]) == appointment.encrypted_blob
+    )
+
+
+def test_to_dict(appointment_data):
+    appointment = Appointment(
+        appointment_data["locator"],
+        appointment_data["start_time"],
+        appointment_data["end_time"],
+        appointment_data["to_self_delay"],
+        appointment_data["encrypted_blob"],
+    )
+
+    dict_appointment = appointment.to_dict()
+
+    assert (
+        appointment_data["locator"] == dict_appointment["locator"]
+        and appointment_data["start_time"] == dict_appointment["start_time"]
+        and appointment_data["end_time"] == dict_appointment["end_time"]
+        and appointment_data["to_self_delay"] == dict_appointment["to_self_delay"]
+        and EncryptedBlob(appointment_data["encrypted_blob"]) == EncryptedBlob(dict_appointment["encrypted_blob"])
+    )
+
+
+def test_to_json(appointment_data):
+    appointment = Appointment(
+        appointment_data["locator"],
+        appointment_data["start_time"],
+        appointment_data["end_time"],
+        appointment_data["to_self_delay"],
+        appointment_data["encrypted_blob"],
+    )
+
+    dict_appointment = json.loads(appointment.to_json())
+
+    assert (
+        appointment_data["locator"] == dict_appointment["locator"]
+        and appointment_data["start_time"] == dict_appointment["start_time"]
+        and appointment_data["end_time"] == dict_appointment["end_time"]
+        and appointment_data["to_self_delay"] == dict_appointment["to_self_delay"]
+        and EncryptedBlob(appointment_data["encrypted_blob"]) == EncryptedBlob(dict_appointment["encrypted_blob"])
+    )
+
+
+def test_from_dict(appointment_data):
+    # The appointment should be build if we don't miss any field
+    appointment = Appointment.from_dict(appointment_data)
+    assert isinstance(appointment, Appointment)
+
+    # Otherwise it should fail
+    for key in appointment_data.keys():
+        prev_val = appointment_data[key]
+        appointment_data[key] = None
+
+        try:
+            Appointment.from_dict(appointment_data)
+            assert False
+
+        except ValueError:
+            appointment_data[key] = prev_val
+            assert True