Use new API Build.getSerial() to get serial number.

Bug: 32935486
Test: RunSettingsRoboTests
Change-Id: I28b8d27d034b4a6c4ae5f29e8311e84e5c423967

tests/robotests/src/com/android/settings/deviceinfo/SerialNumberPreferenceControllerTest.java

@@ -0,0 +1,94 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.settings.deviceinfo;
+
+import android.content.Context;
+import android.support.v7.preference.Preference;
+import android.support.v7.preference.PreferenceScreen;
+
+import com.android.settings.TestConfig;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+
+import static com.google.common.truth.Truth.assertThat;
+import static org.mockito.Answers.RETURNS_DEEP_STUBS;
+import static org.mockito.Matchers.any;
+import static org.mockito.Matchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.never;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+@RunWith(RobolectricTestRunner.class)
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+public class SerialNumberPreferenceControllerTest {
+
+    @Mock(answer = RETURNS_DEEP_STUBS)
+    private Context mContext;
+    @Mock(answer = RETURNS_DEEP_STUBS)
+    private PreferenceScreen mScreen;
+
+    private SerialNumberPreferenceController mController;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+    }
+
+    @Test
+    public void testIsAvaiable_noSerial_shouldReturnFalse() {
+        mController = new SerialNumberPreferenceController(mContext, null);
+
+        assertThat(mController.isAvailable()).isFalse();
+    }
+
+    @Test
+    public void testIsAvaiable_hasSerial_shouldReturnTrue() {
+        mController = new SerialNumberPreferenceController(mContext, "123");
+
+        assertThat(mController.isAvailable()).isTrue();
+    }
+
+    @Test
+    public void testDisplay_noSerial_shouldHidePreference() {
+        when(mScreen.findPreference(anyString())).thenReturn(mock(Preference.class));
+
+        mController = new SerialNumberPreferenceController(mContext, null);
+        mController.displayPreference(mScreen);
+
+        verify(mScreen).removePreference(any(Preference.class));
+    }
+
+    @Test
+    public void testDisplay_hasSerial_shouldSummary() {
+        final String serial = "123";
+        final Preference preference = mock(Preference.class);
+        when(mScreen.findPreference(anyString())).thenReturn(preference);
+
+        mController = new SerialNumberPreferenceController(mContext, serial);
+        mController.displayPreference(mScreen);
+
+        verify(mScreen, never()).removePreference(any(Preference.class));
+        verify(preference).setSummary(serial);
+    }
+}