add ut nullptr check

Signed-off-by: Ncheng_jinsong <chengjinsong2@huawei.com>
Change-Id: Ibc73bd85c4c1a6f7bb289e108ad832d4a62bb9f9

test/unittest/deviceinfo/DeviceInfoUnittest.cpp

@@ -172,7 +172,9 @@ HWTEST_F(DeviceInfoUnittest, TestInterface, TestSize.Level1)
 
 HWTEST_F(DeviceInfoUnittest, TestDeviceInfoProxy1, TestSize.Level1)
 {
-    auto remote = device_info::DeviceInfoKits::GetInstance().GetService()->AsObject();
+    auto remotePtr = device_info::DeviceInfoKits::GetInstance().GetService();
+    ASSERT_NE(remotePtr, nullptr);
+    auto remote = remotePtr->AsObject();
     sptr<device_info::DeviceInfoProxy> proxy = new(std::nothrow) device_info::DeviceInfoProxy(remote);
     ASSERT_NE(proxy, nullptr);