Add unit tests for printer driver, usb device and usb device factory

tests/mocks/MockUsbDevice.hpp

@@ -0,0 +1,57 @@
+/*
+    ptrnt - print labels on linux
+    Copyright (C) 2025  Moritz Martinius
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+ */
+
+#pragma once
+
+#include <gmock/gmock.h>
+
+#include "libusbwrap/interface/IUsbDevice.hpp"
+
+namespace libusbwrap {
+
+/**
+ * @brief GMock implementation of IUsbDevice for unit testing
+ *
+ * This mock allows tests to verify USB device interactions without
+ * requiring actual hardware or libusb context.
+ */
+class MockUsbDevice : public IUsbDevice {
+   public:
+    MOCK_METHOD(bool, open, (), (override));
+    MOCK_METHOD(void, close, (), (override));
+
+    // libusb wrappers
+    MOCK_METHOD(bool, detachKernelDriver, (int interfaceNo), (override));
+    MOCK_METHOD(bool, claimInterface, (int interfaceNo), (override));
+    MOCK_METHOD(bool, releaseInterface, (int interfaceNo), (override));
+    MOCK_METHOD(bool, bulkTransfer,
+                (uint8_t endpoint, const std::vector<uint8_t>& data, int* tx, unsigned int timeout), (override));
+
+    // getters
+    MOCK_METHOD(const usbId, getUsbId, (), (override));
+    MOCK_METHOD(const device::Speed, getSpeed, (), (override));
+    MOCK_METHOD(const uint8_t, getBusNumber, (), (override));
+    MOCK_METHOD(const uint8_t, getPortNumber, (), (override));
+
+    // errors
+    MOCK_METHOD(const Error, getLastError, (), (override));
+    MOCK_METHOD(const std::string, getLastErrorString, (), (override));
+};
+
+}  // namespace libusbwrap