Use mock from Python stdlib and upgrade test requirements versions

mock is part of the Python standard lib since Python 3.3, see also
https://docs.python.org/3/library/unittest.mock.html. Switching to that
allows to remove it from `test/requirements.txt`.

While at it, also updating the package versions in `test/requirements.txt`.

tests/base.py

@@ -1,6 +1,6 @@
 import sys
 from dataclasses import dataclass
-from mock import MagicMock, Mock, patch
+from unittest.mock import MagicMock, Mock, patch
 from typing import Callable
 
 # Prevent importing modules w/Raspi hardware dependencies.

tests/requirements.txt

@@ -1,4 +1,3 @@
-coverage==7.2.1
-mock==4.0.3
-pytest==6.2.4
+coverage==7.3.1
+pytest==7.4.2
 pytest-cov==4.1.0

tests/screenshot_generator/generator.py

@@ -2,7 +2,7 @@ import embit
 import os
 import sys
 import time
-from mock import Mock, patch, MagicMock
+from unittest.mock import Mock, patch, MagicMock
 from seedsigner.helpers import embit_utils
 
 from seedsigner.models.settings import Settings

tests/test_bip85.py

@@ -1,5 +1,5 @@
 import pytest
-from mock import MagicMock
+from unittest.mock import MagicMock
 from seedsigner.models.seed import Seed
 from embit import bip39
 

tests/test_flows_settings.py

@@ -1,7 +1,7 @@
 import os
 from typing import Callable
 
-from mock import PropertyMock, patch
+from unittest.mock import PropertyMock, patch
 
 # Must import test base before the Controller
 from base import FlowTest, FlowStep

tests/test_flows_view.py

@@ -1,4 +1,4 @@
-from mock import patch
+from unittest.mock import patch
 
 # Must import test base before the Controller
 from base import FlowTest, FlowStep