Return a boolean from the mandatory backup transport setter.

Bug: 73813043
Bug: 64012357
Test: cts-tradefed run cts -m CtsDevicePolicyManagerTestCases --test com.android.cts.devicepolicy.DeviceOwnerTest#testGetAndSetMandatoryBackupTransport
Test: cts-tradefed run cts -m CtsBackupHostTestCase --test android.cts.backup.BackupDeviceOwnerHostSideTest

Change-Id: I7f47a41070b767a6be8b986be485b4ad782690cf
diff --git a/services/tests/servicestests/src/com/android/server/devicepolicy/DevicePolicyManagerTest.java b/services/tests/servicestests/src/com/android/server/devicepolicy/DevicePolicyManagerTest.java
index d2fb1ca..43490d3 100644
--- a/services/tests/servicestests/src/com/android/server/devicepolicy/DevicePolicyManagerTest.java
+++ b/services/tests/servicestests/src/com/android/server/devicepolicy/DevicePolicyManagerTest.java
@@ -57,6 +57,7 @@
 import android.app.admin.DevicePolicyManager;
 import android.app.admin.DevicePolicyManagerInternal;
 import android.app.admin.PasswordMetrics;
+import android.app.backup.ISelectBackupTransportCallback;
 import android.content.BroadcastReceiver;
 import android.content.ComponentName;
 import android.content.Intent;
@@ -2264,6 +2265,21 @@
         assertEquals(DevicePolicyManager.POLICY_DISABLE_SCREEN_CAPTURE,
                 intent.getStringExtra(DevicePolicyManager.EXTRA_RESTRICTION));
 
+        // Make the backup transport selection succeed
+        doAnswer(new Answer<Void>() {
+            @Override
+            public Void answer(InvocationOnMock invocation) throws Throwable {
+                ISelectBackupTransportCallback callback =
+                    (ISelectBackupTransportCallback) invocation.getArguments()[1];
+                if (callback != null) {
+                    callback.onSuccess("");
+                }
+                return null;
+            }
+        }).when(getServices().ibackupManager).selectBackupTransportAsync(
+                any(ComponentName.class), any(ISelectBackupTransportCallback.class));
+
+
         // Backups are not mandatory
         intent = dpm.createAdminSupportIntent(DevicePolicyManager.POLICY_MANDATORY_BACKUPS);
         assertNull(intent);