src/printers/P700Printer.cpp

@@ -138,6 +138,10 @@ bool P700Printer::printBitmap(const graphics::Bitmap<graphics::ALPHA8>& bitmap)
 }
 
 bool P700Printer::printMonochromeData(const graphics::MonochromeData& data) {
+    if (!mUsbHndl) {
+        spdlog::error("USB Handle is invalid!");
+        return false;
+    }
     // Send initialization sequence
     // The INITIALIZE command needs to be sent as a 128-byte packet with ESC @ at the end
     std::vector<uint8_t> initCmd(128, 0x00);

tests/mocks/MockUsbDeviceFactory.hpp

@@ -33,6 +33,7 @@ namespace libusbwrap {
  */
 class MockUsbDeviceFactory : public IUsbDeviceFactory {
    public:
+    MOCK_METHOD(bool, init, (), (override));
     MOCK_METHOD(std::vector<std::unique_ptr<IUsbDevice>>, findAllDevices, (), (override));
     MOCK_METHOD(std::vector<std::unique_ptr<IUsbDevice>>, findDevices, (uint16_t vid, uint16_t pid), (override));
 };

tests/printer_service_test/printer_service_test.cpp

@@ -25,32 +25,48 @@
 
 #include "core/PrinterDriverFactory.hpp"
 #include "core/PrinterService.hpp"
+#include "mocks/MockUsbDeviceFactory.hpp"
 
 using ::testing::_;
+using ::testing::Invoke;
 using ::testing::NiceMock;
 using ::testing::Return;
 
 namespace ptprnt::core {
 
+// Helper function to return empty vector of unique_ptrs
+std::vector<std::unique_ptr<libusbwrap::IUsbDevice>> returnEmptyDeviceList() {
+    return {};
+}
+
 // Test fixture for PrinterService tests
 class PrinterServiceTest : public ::testing::Test {
    protected:
     void SetUp() override {
-        // Service under test
+        // Create mock USB device factory
-        service = std::make_unique<PrinterService>();
+        auto mockFactory = std::make_unique<NiceMock<libusbwrap::MockUsbDeviceFactory>>();
+        mockFactoryPtr   = mockFactory.get();
+
+        // Default behavior: init succeeds
+        ON_CALL(*mockFactoryPtr, init()).WillByDefault(Return(true));
+
+        // Default behavior: no devices found
+        ON_CALL(*mockFactoryPtr, findAllDevices()).WillByDefault(Invoke(returnEmptyDeviceList));
+
+        // Inject mock factory into service
+        service = std::make_unique<PrinterService>(std::move(mockFactory));
     }
 
     void TearDown() override { service.reset(); }
 
     std::unique_ptr<PrinterService> service;
+    libusbwrap::MockUsbDeviceFactory* mockFactoryPtr;  // Non-owning pointer for expectations
 };
 
 // Test: PrinterService initialization
 TEST_F(PrinterServiceTest, InitializeSuccess) {
-    // PrinterService::initialize() calls UsbDeviceFactory::init()
+    EXPECT_CALL(*mockFactoryPtr, init()).WillOnce(Return(true));
-    // This will attempt to initialize libusb - we can't easily mock this
+
-    // without dependency injection, but we can test the call succeeds
-    // when libusb is available
     EXPECT_TRUE(service->initialize());
 }
 
@@ -58,37 +74,35 @@ TEST_F(PrinterServiceTest, InitializeSuccess) {
 TEST_F(PrinterServiceTest, DetectPrintersNoneFound) {
     service->initialize();
 
+    // Mock returns empty device list - no real USB enumeration happens
+    EXPECT_CALL(*mockFactoryPtr, findAllDevices()).WillOnce(Invoke(returnEmptyDeviceList));
+
     auto printers = service->detectPrinters();
 
-    // With no compatible USB devices, we should get an empty list
+    // Should get empty list since mock returns no devices
-    // (This depends on actual USB devices present, so it might find real hardware)
+    EXPECT_EQ(printers.size(), 0);
-    // In a real test environment without hardware, this should be empty
-    EXPECT_GE(printers.size(), 0);  // Non-negative count
 }
 
-// Test: Select printer with auto-detect
+// Test: Select printer with auto-detect when none found
-TEST_F(PrinterServiceTest, SelectPrinterAuto) {
+TEST_F(PrinterServiceTest, SelectPrinterAutoNoneFound) {
     service->initialize();
-    service->detectPrinters();
+
+    // Mock returns empty device list
+    EXPECT_CALL(*mockFactoryPtr, findAllDevices()).WillOnce(Invoke(returnEmptyDeviceList));
 
     auto printer = service->selectPrinter("auto");
 
-    // This will be nullptr if no printers detected
+    // Should be nullptr since no printers detected
-    // In test environment without hardware, expect nullptr
-    // (Test passes either way - just exercises the code path)
-    if (printer != nullptr) {
-        EXPECT_NE(printer, nullptr);
-        EXPECT_EQ(service->getCurrentPrinter(), printer);
-    } else {
     EXPECT_EQ(printer, nullptr);
-    }
+    EXPECT_EQ(service->getCurrentPrinter(), nullptr);
 }
 
-// Test: Select non-existent printer
+// Test: Select non-existent printer by name
-TEST_F(PrinterServiceTest, SelectPrinterNotFound) {
+TEST_F(PrinterServiceTest, SelectPrinterByNameNotFound) {
     service->initialize();
-    service->detectPrinters();
 
+    // This test doesn't need USB mocking since selectPrinter("name")
+    // uses PrinterDriverFactory directly, not USB enumeration
     auto printer = service->selectPrinter("NonExistentPrinter");
 
     EXPECT_EQ(printer, nullptr);