Add a plus button to the mobile pref on Network & internet page

On the Network & internet page, we have a "Mobile network" pref that in
single-SIM mode leads to a detail page for the current SIM. In multi-SIM
mode it has more complicated behavior (leading either to details about
the current subscription if there is only one, or a list of
subscriptions if more than one).

One of the things we wanted to add was a shortcut to add another eSIM
subscription. So this CL adds a plus button control on the right of the
preference which leads to a flow to add another mobile subscription via
the eSIM manager.

Bug: 116349402
Test: make RunSettingsRoboTests
Change-Id: I38e0031e3bd603e93c45dcb4557750e7bc1b8b5a

tests/robotests/src/com/android/settings/widget/AddPreferenceTest.java

@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2019 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.widget;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import static org.mockito.ArgumentMatchers.eq;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.spy;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.content.Context;
+import android.view.View;
+
+import com.android.settings.R;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.MockitoAnnotations;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+import androidx.preference.PreferenceViewHolder;
+
+@RunWith(RobolectricTestRunner.class)
+public class AddPreferenceTest {
+
+    private Context mContext;
+    private PreferenceViewHolder mViewHolder;
+    private View mWidgetFrame;
+    private View mAddWidget;
+    private AddPreference mPreference;
+
+    @Before
+    public void setUp() {
+        mContext = RuntimeEnvironment.application;
+        mPreference = new AddPreference(mContext, null);
+
+        final View view = spy(View.inflate(mContext, mPreference.getLayoutResource(), null));
+        mViewHolder = PreferenceViewHolder.createInstanceForTests(view);
+        mWidgetFrame = view.findViewById(android.R.id.widget_frame);
+        mAddWidget = spy(View.inflate(mContext, mPreference.getSecondTargetResId(), null));
+        when(mViewHolder.findViewById(mPreference.getAddWidgetResId())).thenReturn(mAddWidget);
+    }
+
+    @Test
+    public void onBindViewHolder_noListener_addButtonNotVisible() {
+        mPreference.onBindViewHolder(mViewHolder);
+        assertThat(mPreference.shouldHideSecondTarget()).isTrue();
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.GONE);
+    }
+
+    @Test
+    public void onBindViewHolder_hasListener_addButtonVisible() {
+        mPreference.setOnAddClickListener(p -> {});
+        mPreference.onBindViewHolder(mViewHolder);
+        assertThat(mPreference.shouldHideSecondTarget()).isFalse();
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.VISIBLE);
+    }
+
+    @Test
+    public void setOnAddClickListener_listenerAddedAfterBinding_addButtonBecomesVisible() {
+        mPreference.onBindViewHolder(mViewHolder);
+        assertThat(mPreference.shouldHideSecondTarget()).isTrue();
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.GONE);
+
+        mPreference.setOnAddClickListener(p -> {});
+        assertThat(mPreference.shouldHideSecondTarget()).isFalse();
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.VISIBLE);
+    }
+
+    @Test
+    public void setOnAddClickListener_listenerRemovedAfterBinding_addButtonNotVisible() {
+        mPreference.setOnAddClickListener(p -> {});
+
+        mPreference.onBindViewHolder(mViewHolder);
+        assertThat(mPreference.shouldHideSecondTarget()).isFalse();
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.VISIBLE);
+
+        mPreference.setOnAddClickListener(null);
+        assertThat(mPreference.shouldHideSecondTarget()).isTrue();
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.GONE);
+    }
+
+    @Test
+    public void setOnAddClickListener_listenerAddedAndRemovedAfterBinding_addButtonNotVisible() {
+        mPreference.onBindViewHolder(mViewHolder);
+        assertThat(mPreference.shouldHideSecondTarget()).isTrue();
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.GONE);
+
+        mPreference.setOnAddClickListener(p -> {});
+        assertThat(mPreference.shouldHideSecondTarget()).isFalse();
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.VISIBLE);
+
+        mPreference.setOnAddClickListener(null);
+        assertThat(mPreference.shouldHideSecondTarget()).isTrue();
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.GONE);
+    }
+
+    @Test
+    public void onClick_noListener_noCrash() {
+        mPreference.onBindViewHolder(mViewHolder);
+        // should be no crash here
+        mPreference.onClick(mAddWidget);
+    }
+
+    @Test
+    public void onClick_hasListenerBeforeBind_firesCorrectly() {
+        final AddPreference.OnAddClickListener listener = mock(
+                AddPreference.OnAddClickListener.class);
+        mPreference.setOnAddClickListener(listener);
+
+        mPreference.onBindViewHolder(mViewHolder);
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.VISIBLE);
+
+        mPreference.onClick(mAddWidget);
+        verify(listener).onAddClick(eq(mPreference));
+    }
+
+    @Test
+    public void onClick_listenerAddedAfterBind_firesCorrectly() {
+        mPreference.onBindViewHolder(mViewHolder);
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.GONE);
+
+        final AddPreference.OnAddClickListener listener = mock(
+                AddPreference.OnAddClickListener.class);
+        mPreference.setOnAddClickListener(listener);
+        assertThat(mWidgetFrame.getVisibility()).isEqualTo(View.VISIBLE);
+
+        mPreference.onClick(mAddWidget);
+        verify(listener).onAddClick(eq(mPreference));
+    }
+}