Prevent NPE in CoreSettingsObserverTest

The constructor of AppBatteryTracker#AppBatteryPolicy updated in a
commit [1] and now that the test need to be changed, similar to another
previous commit [2].

[1] Iffa7ff2b7fb8f14f1a54359d72d936c721d27904
[2] I2f808828eba79147fea3a88279effffb7b5b20a4

Bug: 245454635
Test: CoreSettingsObserverTest
Change-Id: I1e890e93868b605fe9c413a8749c694d6f59c1c3
diff --git a/services/tests/servicestests/src/com/android/server/am/CoreSettingsObserverTest.java b/services/tests/servicestests/src/com/android/server/am/CoreSettingsObserverTest.java
index 693bc7d..574aaf0 100644
--- a/services/tests/servicestests/src/com/android/server/am/CoreSettingsObserverTest.java
+++ b/services/tests/servicestests/src/com/android/server/am/CoreSettingsObserverTest.java
@@ -24,10 +24,12 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.anyInt;
+import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.when;
 
 import android.content.Context;
 import android.content.res.Resources;
+import android.content.res.TypedArray;
 import android.os.Bundle;
 import android.os.Handler;
 import android.provider.Settings;
@@ -99,6 +101,9 @@
         // To prevent NullPointerException at the constructor of ActivityManagerConstants.
         when(mResources.getStringArray(anyInt())).thenReturn(new String[0]);
         when(mResources.getIntArray(anyInt())).thenReturn(new int[0]);
+        final TypedArray mockTypedArray = mock(TypedArray.class);
+        when(mockTypedArray.length()).thenReturn(1);
+        when(mResources.obtainTypedArray(anyInt())).thenReturn(mockTypedArray);
 
         mAms = new ActivityManagerService(new TestInjector(mContext),
                 mServiceThreadRule.getThread());