Enforce disallow switch user in user settings

Disallow the following actions which result in switch user when DISALLOW_USER_SWITCH is set
- Creating guest
- Showing user setup dialog for newly created user
- Clicking uninitialized user preference

Bug: 71694430
Test: CTSVerifier DeviceOwnerPositiveTest - DISALLOW_USER_SWITCH
Test: m -j ROBOTEST_FILTER=UserCapabilitiesTest RunSettingsRoboTests
Test: m -j ROBOTEST_FILTER=AddUserWhenLockedPreferenceController RunSettingsRoboTests
Test: m -j ROBOTEST_FILTER=UserSettingsTest RunSettingsRoboTests
Change-Id: Ia4c7e7b4947bfaf2ebeef4d32a473bdac542d6a6

tests/robotests/src/com/android/settings/users/UserCapabilitiesTest.java

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2018 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.users;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.os.UserManager;
+
+import com.android.settings.TestConfig;
+import com.android.settings.testutils.SettingsRobolectricTestRunner;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.annotation.Config;
+
+@RunWith(SettingsRobolectricTestRunner.class)
+@Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
+public class UserCapabilitiesTest {
+
+    @Mock
+    private Context mContext;
+    @Mock
+    private UserManager mUserManager;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+        when(mContext.getSystemService(Context.USER_SERVICE)).thenReturn(mUserManager);
+    }
+
+    @Test
+    public void disallowUserSwitchWhenRestrictionIsSet() {
+        when(mUserManager.hasUserRestriction(UserManager.DISALLOW_USER_SWITCH)).thenReturn(true);
+
+        UserCapabilities userCapabilities = UserCapabilities.create(mContext);
+        userCapabilities.updateAddUserCapabilities(mContext);
+
+        assertThat(userCapabilities.mDisallowSwitchUser).isTrue();
+    }
+
+    @Test
+    public void allowUserSwitchWhenRestrictionIsNotSet() {
+        when(mUserManager.hasUserRestriction(UserManager.DISALLOW_USER_SWITCH)).thenReturn(false);
+
+        UserCapabilities userCapabilities = UserCapabilities.create(mContext);
+        userCapabilities.updateAddUserCapabilities(mContext);
+
+        assertThat(userCapabilities.mDisallowSwitchUser).isFalse();
+    }
+}