Introduce concept of DockUser

Dreams and docking often refers to "user zero" or "system user".
But more generally, the special user for dreams or switching-to-on-docking
need not be user 0, and in fact won't be in certain modes. So this needs updating.

Test: the files mentioned in the topic
Bug: 257333623
Change-Id: If068aa79a770bed4abf3f7ca1859a95cd1eb4ecd
Merged-In: If068aa79a770bed4abf3f7ca1859a95cd1eb4ecd

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

@@ -0,0 +1,98 @@
+/*
+ * Copyright (C) 2022 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.doReturn;
+import static org.mockito.Mockito.spy;
+
+import android.content.Context;
+
+import androidx.fragment.app.FragmentActivity;
+import androidx.test.core.app.ApplicationProvider;
+
+import com.android.settings.R;
+import com.android.settings.testutils.shadow.ShadowFragment;
+import com.android.settingslib.widget.CandidateInfo;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.annotation.Config;
+
+import java.util.List;
+
+@RunWith(RobolectricTestRunner.class)
+@Config(shadows = {ShadowFragment.class})
+public class TimeoutToDockUserSettingsTest {
+    @Mock
+    private FragmentActivity mActivity;
+
+    private TimeoutToDockUserSettings mSettings;
+
+    private String[] mEntries;
+    private String[] mValues;
+
+    @Before
+    public void setUp() {
+        MockitoAnnotations.initMocks(this);
+
+        final Context context = spy(ApplicationProvider.getApplicationContext());
+        mEntries = context.getResources().getStringArray(
+                R.array.switch_to_dock_user_when_docked_timeout_entries);
+        mValues = context.getResources().getStringArray(
+                R.array.switch_to_dock_user_when_docked_timeout_values);
+        mSettings = spy(new TimeoutToDockUserSettings());
+
+        doReturn(context).when(mSettings).getContext();
+        doReturn(mActivity).when(mSettings).getActivity();
+
+        mSettings.onAttach(context);
+    }
+
+    @Test
+    public void getCandidates_returnsACandidateForEachEntry() {
+        final List<? extends CandidateInfo> candidates = mSettings.getCandidates();
+
+        for (int i = 0; i < mEntries.length; i++) {
+            assertThat(candidates.get(i).loadLabel().toString()).isEqualTo(mEntries[i]);
+        }
+    }
+
+    @Test
+    public void defaultKey_settingNotSet_shouldReturnFirstValueAsDefault() {
+        assertThat(mSettings.getDefaultKey()).isEqualTo(mValues[0]);
+    }
+
+    @Test
+    public void defaultKey_setToFirstValue_shouldSaveToSettings() {
+        final String expectedKey = mValues[0];
+        mSettings.setDefaultKey(expectedKey);
+        assertThat(mSettings.getDefaultKey()).isEqualTo(expectedKey);
+    }
+
+    @Test
+    public void defaultKey_setToSecondValue_shouldSaveToSettings() {
+        final String expectedKey = mValues[1];
+        mSettings.setDefaultKey(expectedKey);
+        assertThat(mSettings.getDefaultKey()).isEqualTo(expectedKey);
+    }
+}