diff --git a/tests/unit/src/com/android/settings/network/telephony/NetworkSelectSettingsTest.java b/tests/unit/src/com/android/settings/network/telephony/NetworkSelectSettingsTest.java
new file mode 100644
index 00000000000..3256aba3877
--- /dev/null
+++ b/tests/unit/src/com/android/settings/network/telephony/NetworkSelectSettingsTest.java
@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2020 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.network.telephony;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.doReturn;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.telephony.CellIdentityLte;
+import android.telephony.CellIdentityWcdma;
+import android.telephony.CellInfoLte;
+import android.telephony.CellInfoWcdma;
+import android.telephony.SubscriptionManager;
+import android.telephony.TelephonyManager;
+
+import androidx.preference.PreferenceCategory;
+import androidx.preference.PreferenceManager;
+import androidx.test.annotation.UiThreadTest;
+import androidx.test.core.app.ApplicationProvider;
+import androidx.test.ext.junit.runners.AndroidJUnit4;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+
+import java.util.Arrays;
+
+@RunWith(AndroidJUnit4.class)
+public class NetworkSelectSettingsTest {
+    private static final int SUB_ID = 2;
+    private static final String CARRIER_NAME1 = "CarrierName1";
+    private static final String CARRIER_NAME2 = "CarrierName2";
+
+    @Mock
+    private TelephonyManager mTelephonyManager;
+    @Mock
+    private SubscriptionManager mSubscriptionManager;
+    @Mock
+    private PreferenceManager mPreferenceManager;
+    @Mock
+    private SharedPreferences mSharedPreferences;
+
+    private CellInfoWcdma mCellInfo1 = new CellInfoWcdma();
+    private CellIdentityWcdma mCellId1 = new CellIdentityWcdma();
+    private CellInfoLte mCellInfo2 = new CellInfoLte();
+    private CellIdentityLte mCellId2 = new CellIdentityLte();
+
+    private Context mContext;
+
+    private PreferenceCategory mPreferenceCategory;
+
+    private NetworkSelectSettings mNetworkSelectSettings;
+
+    @Before
+    @UiThreadTest
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+
+        mContext = spy(ApplicationProvider.getApplicationContext());
+        when(mContext.getSystemService(Context.TELEPHONY_SERVICE)).thenReturn(mTelephonyManager);
+        when(mContext.getSystemService(SubscriptionManager.class)).thenReturn(mSubscriptionManager);
+        when(mTelephonyManager.createForSubscriptionId(SUB_ID)).thenReturn(mTelephonyManager);
+
+        mCellInfo1.setRegistered(true);
+        mCellInfo1.setCellIdentity(mCellId1);
+        mCellId1.setOperatorAlphaLong(CARRIER_NAME1);
+        mCellInfo2.setRegistered(false);
+        mCellInfo2.setCellIdentity(mCellId2);
+        mCellId2.setOperatorAlphaLong(CARRIER_NAME2);
+
+        doReturn(mSharedPreferences).when(mPreferenceManager).getSharedPreferences();
+        mPreferenceCategory = spy(new PreferenceCategory(mContext));
+        doReturn(mPreferenceManager).when(mPreferenceCategory).getPreferenceManager();
+
+        mNetworkSelectSettings = spy(new NetworkSelectSettings());
+        doReturn(mContext).when(mNetworkSelectSettings).getContext();
+        doReturn(mPreferenceManager).when(mNetworkSelectSettings).getPreferenceManager();
+        doReturn(mContext).when(mPreferenceManager).getContext();
+
+        mNetworkSelectSettings.mTelephonyManager = mTelephonyManager;
+        mNetworkSelectSettings.mPreferenceCategory = mPreferenceCategory;
+        mNetworkSelectSettings.mCellInfoList = Arrays.asList(mCellInfo1, mCellInfo2);
+    }
+
+    @Test
+    public void updateAllPreferenceCategory_correctOrderingPreference() {
+        mNetworkSelectSettings.updateAllPreferenceCategory();
+
+        assertThat(mPreferenceCategory.getPreferenceCount()).isEqualTo(2);
+        final NetworkOperatorPreference preference =
+                (NetworkOperatorPreference) mPreferenceCategory.getPreference(1);
+        assertThat(preference.getOperatorName()).isEqualTo(mCellId2.getOperatorAlphaLong());
+    }
+
+    @Test
+    public void updateForbiddenPlmns_forbiddenPlmnsNull_shouldNotCrash() {
+        when(mTelephonyManager.getForbiddenPlmns()).thenReturn(null);
+
+        // Should not Crash
+        mNetworkSelectSettings.updateForbiddenPlmns();
+    }
+}