Merge "dm_test.cpp: DeleteDeviceWithTimeout asserts that unique path is deleted" into main

    ASSERT_TRUE(dm.GetDmDevicePathByName("libdm-test-dm-linear", &path));

    ASSERT_EQ(0, access(path.c_str(), F_OK));

    std::string unique_path;

    ASSERT_TRUE(dm.GetDeviceUniquePath("libdm-test-dm-linear", &unique_path));

    ASSERT_EQ(0, access(unique_path.c_str(), F_OK));

    ASSERT_TRUE(dm.DeleteDevice("libdm-test-dm-linear", 5s));

    ASSERT_EQ(DmDeviceState::INVALID, dm.GetState("libdm-test-dm-linear"));

    ASSERT_NE(0, access(path.c_str(), F_OK));

    // Check that unique path of this device has been deleteted.

    // Previously this test case used to check that dev node (i.e. /dev/block/dm-XX) has been

    // deleted. However, this introduces a race condition, ueventd will remove the unique symlink

    // (i.e. /dev/block/mapper/by-uuid/...) **before** removing the device node, while DeleteDevice

    // API synchronizes on the unique symlink being deleted.

    ASSERT_NE(0, access(unique_path.c_str(), F_OK));

    ASSERT_EQ(ENOENT, errno);

}