diff --git a/gpio_handler_unittest.cc b/gpio_handler_unittest.cc
new file mode 100644
index 0000000..a133ac7
--- /dev/null
+++ b/gpio_handler_unittest.cc
@@ -0,0 +1,58 @@
+// Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <gtest/gtest.h>
+
+#include "update_engine/gpio_handler.h"
+#include "update_engine/gpio_mock_udev_interface.h"
+
+// Some common strings used by the different cooperating mocks for this module.
+// We use preprocessor constants to allow concatenation at compile-time.
+#define MOCK_GPIO_CHIP_ID     "100"
+#define MOCK_DUTFLAGA_GPIO_ID "101"
+#define MOCK_DUTFLAGB_GPIO_ID "102"
+#define MOCK_SYSFS_PREFIX     "/mock/sys/class/gpio"
+
+namespace chromeos_update_engine {
+
+class StandardGpioHandlerTest : public ::testing::Test {};
+
+TEST(StandardGpioHandlerTest, NormalInitTest) {
+  // Ensure that initialization of the GPIO module works as expected, and that
+  // all udev resources are deallocated afterwards.  The mock file descriptor is
+  // not to be used.
+  StandardGpioMockUdevInterface mock_udev;
+  StandardGpioHandler gpio_hander(&mock_udev, false);
+  mock_udev.ExpectAllResourcesDeallocated();
+  mock_udev.ExpectDiscoverySuccess();
+}
+
+TEST(StandardGpioHandlerTest, MultiGpioChipInitTest) {
+  // Attempt GPIO discovery with a udev mock that returns two GPIO chip devices.
+  // It should fail, of course.  The mock file descriptor is not to be used.
+  MultiChipGpioMockUdevInterface mock_udev;
+  StandardGpioHandler gpio_handler(&mock_udev, false);
+  mock_udev.ExpectAllResourcesDeallocated();
+  mock_udev.ExpectDiscoveryFail();
+}
+
+TEST(StandardGpioHandlerTest, NormalModeGpioSignalingTest) {
+  // Initialize the GPIO module, run the signaling procedure, ensure that it
+  // concluded that this is a normal mode run.
+  StandardGpioMockUdevInterface mock_udev;
+  StandardGpioHandler gpio_handler(&mock_udev, false);
+  EXPECT_FALSE(gpio_handler.IsTestModeSignaled());
+  mock_udev.ExpectAllResourcesDeallocated();
+}
+
+TEST(StandardGpioHandlerTest, DeferredInitNormalModeGpioSignalingTest) {
+  // Initialize the GPIO module with deferred discovery, run the signaling
+  // procedure, ensure that it concluded that this is a normal mode run.
+  StandardGpioMockUdevInterface mock_udev;
+  StandardGpioHandler gpio_handler(&mock_udev, true);
+  EXPECT_FALSE(gpio_handler.IsTestModeSignaled());
+  mock_udev.ExpectAllResourcesDeallocated();
+}
+
+}  // namespace chromeos_update_engine