Hide "Changes made by your organization's admin" when empty

The admin of a manged device can take a number actions that will be
listed in the "Changes made by your organization's admin" section of
Settings. If the admin has not taken any such actions, the section
will be empty and should be hidden. This is accomplished by having a
PreferenceController for the section that observes the state of the
PreferenceControllers inside it.

Bug: 35912953
Test: m RunSettingsRoboTests

Change-Id: Ia95754493ee6c5a19b4aa9731fd56fd558e61849

tests/robotests/src/com/android/settings/enterprise/EnterprisePrivacySettingsTest.java

@@ -16,12 +16,16 @@
 
 package com.android.settings.enterprise;
 
+import android.app.Application;
 import android.content.Context;
+import android.content.res.Resources;
+import android.content.res.XmlResourceParser;
 
 import com.android.internal.logging.nano.MetricsProto.MetricsEvent;
 import com.android.settings.R;
 import com.android.settings.SettingsRobolectricTestRunner;
 import com.android.settings.TestConfig;
+import com.android.settings.core.DynamicAvailabilityPreferenceController;
 import com.android.settings.core.PreferenceController;
 import com.android.settings.testutils.FakeFeatureFactory;
 
@@ -31,10 +35,14 @@ import org.junit.runner.RunWith;
 import org.mockito.Answers;
 import org.mockito.Mock;
 import org.mockito.MockitoAnnotations;
+import org.robolectric.RuntimeEnvironment;
 import org.robolectric.annotation.Config;
 import org.robolectric.shadows.ShadowApplication;
+import org.xmlpull.v1.XmlPullParser;
 
+import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 
 import static com.google.common.truth.Truth.assertThat;
 import static org.mockito.Mockito.when;
@@ -46,6 +54,9 @@ import static org.mockito.Mockito.when;
 @Config(manifest = TestConfig.MANIFEST_PATH, sdk = TestConfig.SDK_VERSION)
 public final class EnterprisePrivacySettingsTest {
 
+    private final static String RESOURCES_NAMESPACE = "http://schemas.android.com/apk/res/android";
+    private final static String ATTR_KEY = "key";
+
     @Mock(answer = Answers.RETURNS_DEEP_STUBS)
     private Context mContext;
     private FakeFeatureFactory mFeatureFactory;
@@ -101,23 +112,24 @@ public final class EnterprisePrivacySettingsTest {
     }
 
     @Test
-    public void getPreferenceControllers() {
+    public void getPreferenceControllers() throws Exception {
         final List<PreferenceController> controllers = mSettings.getPreferenceControllers(
                 ShadowApplication.getInstance().getApplicationContext());
         verifyPreferenceControllers(controllers);
     }
 
     @Test
-    public void getSearchIndexProviderPreferenceControllers() {
+    public void getSearchIndexProviderPreferenceControllers() throws Exception {
         final List<PreferenceController> controllers
                 = EnterprisePrivacySettings.SEARCH_INDEX_DATA_PROVIDER.getPreferenceControllers(
                         ShadowApplication.getInstance().getApplicationContext());
         verifyPreferenceControllers(controllers);
     }
 
-    private void verifyPreferenceControllers(List<PreferenceController> controllers) {
+    private void verifyPreferenceControllers(List<PreferenceController> controllers)
+            throws Exception {
         assertThat(controllers).isNotNull();
-        assertThat(controllers.size()).isEqualTo(15);
+        assertThat(controllers.size()).isEqualTo(16);
         int position = 0;
         assertThat(controllers.get(position++)).isInstanceOf(NetworkLogsPreferenceController.class);
         assertThat(controllers.get(position++)).isInstanceOf(BugReportsPreferenceController.class);
@@ -137,14 +149,71 @@ public final class EnterprisePrivacySettingsTest {
                 AlwaysOnVpnCurrentUserPreferenceController.class);
         assertThat(controllers.get(position++)).isInstanceOf(
                 AlwaysOnVpnManagedProfilePreferenceController.class);
+        assertThat(controllers.get(position++)).isInstanceOf(ImePreferenceController.class);
         assertThat(controllers.get(position++)).isInstanceOf(
                 GlobalHttpProxyPreferenceController.class);
         assertThat(controllers.get(position++)).isInstanceOf(
                 CaCertsPreferenceController.class);
+        final PreferenceController exposureChangesCategoryController = controllers.get(position);
+        final int exposureChangesCategoryControllerIndex = position;
+        assertThat(controllers.get(position++)).isInstanceOf(
+                ExposureChangesCategoryPreferenceController.class);
         assertThat(controllers.get(position++)).isInstanceOf(
                 FailedPasswordWipeCurrentUserPreferenceController.class);
         assertThat(controllers.get(position++)).isInstanceOf(
                 FailedPasswordWipeManagedProfilePreferenceController.class);
-        assertThat(controllers.get(position++)).isInstanceOf(ImePreferenceController.class);
+
+        // The "Changes made by your organization's admin" category is hidden when all Preferences
+        // inside it become unavailable. To do this correctly, the category's controller must:
+        // a) Observe the availability of all Preferences in the category and
+        // b) Be listed after those Preferences' controllers, so that availability is updated in
+        //    the correct order
+
+        // Find all Preferences in the category.
+        final XmlResourceParser parser = RuntimeEnvironment.application.getResources().getXml(
+                R.xml.enterprise_privacy_settings);
+        boolean done = false;
+        int type;
+        final Set<String> expectedObserved = new HashSet<>();
+        while (!done && (type = parser.next()) != XmlPullParser.END_DOCUMENT) {
+            if (type != XmlPullParser.START_TAG || !"exposure_changes_category".equals(
+                    parser.getAttributeValue(RESOURCES_NAMESPACE, ATTR_KEY))) {
+                continue;
+            }
+            int depth = 1;
+            while ((type = parser.next()) != XmlPullParser.END_DOCUMENT) {
+                if (type == XmlPullParser.START_TAG) {
+                    final String key = parser.getAttributeValue(RESOURCES_NAMESPACE, ATTR_KEY);
+                    if (key != null) {
+                        expectedObserved.add(key);
+                    }
+                    depth++;
+                } else if (type == XmlPullParser.END_TAG) {
+                    depth--;
+                    if (depth == 0) {
+                        done = true;
+                        break;
+                    }
+                }
+            }
+        }
+
+        // Find all Preferences the category's controller is observing.
+        final Set<String> actualObserved = new HashSet<>();
+        int maxObservedIndex = -1;
+        for (int i = 0; i < controllers.size(); i++) {
+            final PreferenceController controller = controllers.get(i);
+            if (controller instanceof DynamicAvailabilityPreferenceController &&
+                    ((DynamicAvailabilityPreferenceController) controller).getAvailabilityObserver()
+                            == exposureChangesCategoryController) {
+                actualObserved.add(controller.getPreferenceKey());
+                maxObservedIndex = i;
+            }
+        }
+
+        // Verify that the category's controller is observing the Preferences inside it.
+        assertThat(actualObserved).isEqualTo(expectedObserved);
+        // Verify that the category's controller is listed after the Preferences' controllers.
+        assertThat(maxObservedIndex).isLessThan(exposureChangesCategoryControllerIndex);
     }
 }