mock signal registration to prevent errors when running tests under pypy

test/unit/conftest.py

@@ -97,7 +97,13 @@ def run(self, *args, **kwargs):
 
 
 @pytest.fixture
-def b2_cli(console_tool_class):
+def mock_signal():
+    with mock.patch('signal.signal'):
+        yield
+
+
+@pytest.fixture
+def b2_cli(console_tool_class, mock_signal):
     cli_tester = ConsoleToolTester()
     # Because of the magic the pytest does on importing and collecting fixtures,
     # ConsoleToolTester is not injected with the `unit_test_console_tool_class`