Update logging util to not crash on null

The logging for the wifi access points could cause a crash if
a bad scan result is passed in for any reason. This CL updates
it to be resilient to that by doing a best effort logging of
the scan results.

Bug: 74507895
Test: robotests
Change-Id: I4eaf948d7279374b1f4d009ef6f4fd0119f22ab7

packages/SettingsLib/src/com/android/settingslib/wifi/WifiUtils.java

@@ -76,7 +76,8 @@ public class WifiUtils {
      * ["rssi 5Ghz", "num results on 5GHz" / "rssi 5Ghz", "num results on 5GHz"]
      * For instance [-40,5/-30,2]
      */
-    private static String getVisibilityStatus(AccessPoint accessPoint) {
+    @VisibleForTesting
+    static String getVisibilityStatus(AccessPoint accessPoint) {
         final WifiInfo info = accessPoint.getInfo();
         StringBuilder visibility = new StringBuilder();
         StringBuilder scans24GHz = new StringBuilder();
@@ -110,6 +111,9 @@ public class WifiUtils {
         // TODO: sort list by RSSI or age
         long nowMs = SystemClock.elapsedRealtime();
         for (ScanResult result : accessPoint.getScanResults()) {
+            if (result == null) {
+                continue;
+            }
             if (result.frequency >= AccessPoint.LOWER_FREQ_5GHZ
                     && result.frequency <= AccessPoint.HIGHER_FREQ_5GHZ) {
                 // Strictly speaking: [4915, 5825]

packages/SettingsLib/tests/robotests/src/com/android/settingslib/wifi/WifiUtilsTest.java

@@ -18,6 +18,7 @@ package com.android.settingslib.wifi;
 import static com.google.common.truth.Truth.assertThat;
 import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.when;
 
 import android.content.Context;
@@ -31,6 +32,7 @@ import android.os.Bundle;
 import android.os.Parcelable;
 import android.os.SystemClock;
 import android.text.format.DateUtils;
+import android.util.ArraySet;
 
 import com.android.settingslib.R;
 import com.android.settingslib.SettingsLibRobolectricTestRunner;
@@ -43,6 +45,7 @@ import org.mockito.MockitoAnnotations;
 import org.robolectric.RuntimeEnvironment;
 
 import java.util.ArrayList;
+import java.util.Set;
 
 @RunWith(SettingsLibRobolectricTestRunner.class)
 public class WifiUtilsTest {
@@ -56,6 +59,8 @@ public class WifiUtilsTest {
     private RssiCurve mockBadgeCurve;
     @Mock
     private WifiNetworkScoreCache mockWifiNetworkScoreCache;
+    @Mock
+    private AccessPoint mAccessPoint;
 
     @Before
     public void setUp() {
@@ -84,6 +89,15 @@ public class WifiUtilsTest {
         assertThat(summary.contains(mContext.getString(R.string.speed_label_very_fast))).isTrue();
     }
 
+    @Test
+    public void testGetVisibilityStatus_nullResultDoesNotCrash() {
+        doReturn(null).when(mAccessPoint).getInfo();
+        Set<ScanResult> set = new ArraySet<>();
+        set.add(null);
+        doReturn(set).when(mAccessPoint).getScanResults();
+        WifiUtils.getVisibilityStatus(mAccessPoint);
+    }
+
     private static ArrayList<ScanResult> buildScanResultCache() {
         ArrayList<ScanResult> scanResults = new ArrayList<>();
         for (int i = 0; i < 5; i++) {