Add test cases for BalanceSeekBar

Bug: 123722274
Test: Manual
      make RunSettingsRoboTests ROBOTEST_FILTER=BalanceSeekBar

Change-Id: Ie6b560b2f92d78a0d3bd7ddb0e0d0a85c7803827

tests/robotests/src/com/android/settings/accessibility/BalanceSeekBarPreferenceTest.java

@@ -0,0 +1,65 @@
+/*
+ * 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.accessibility;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import android.content.Context;
+import android.util.AttributeSet;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.widget.LinearLayout;
+
+import androidx.preference.PreferenceViewHolder;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.RobolectricTestRunner;
+import org.robolectric.RuntimeEnvironment;
+
+@RunWith(RobolectricTestRunner.class)
+public class BalanceSeekBarPreferenceTest {
+    private static final int BALANCE_CENTER_VALUE = 100;
+    private static final int BALANCE_MAX_VALUE = 200;
+
+    private Context mContext;
+    private AttributeSet mAttrs;
+    private PreferenceViewHolder mHolder;
+    private BalanceSeekBar mSeekBar;
+    private BalanceSeekBarPreference mSeekBarPreference;
+
+    @Before
+    public void setUp() {
+        mContext = RuntimeEnvironment.application;
+        mSeekBarPreference = new BalanceSeekBarPreference(mContext, mAttrs);
+        LayoutInflater inflater = LayoutInflater.from(mContext);
+        final View view =
+                inflater.inflate(mSeekBarPreference.getLayoutResource(),
+                        new LinearLayout(mContext), false);
+        mHolder = PreferenceViewHolder.createInstanceForTests(view);
+        mSeekBar = (BalanceSeekBar) view.findViewById(com.android.internal.R.id.seekbar);
+    }
+
+    @Test
+    public void seekBarPreferenceOnBindViewHolder_shouldInitSeekBarValue() {
+        mSeekBarPreference.onBindViewHolder(mHolder);
+
+        assertThat(mSeekBar.getMax()).isEqualTo(BALANCE_MAX_VALUE);
+        assertThat(mSeekBar.getProgress()).isEqualTo(BALANCE_CENTER_VALUE);
+    }
+}