1/*
2 * Copyright (C) 2017 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License
15 */
16
17package com.android.internal.graphics;
18
19import android.graphics.Color;
20import android.support.test.filters.SmallTest;
21
22import org.junit.Test;
23
24import static org.junit.Assert.assertTrue;
25
26@SmallTest
27public class ColorUtilsTest {
28
29    @Test
30    public void calculateMinimumBackgroundAlpha_satisfiestContrast() {
31
32        int alpha = ColorUtils.calculateMinimumBackgroundAlpha(Color.WHITE, Color.BLACK, 4.5f);
33        assertTrue("Alpha doesn't need to be 255 to satisfy contrast", alpha < 255);
34
35        int worstCase = ColorUtils.blendARGB(Color.WHITE, Color.BLACK, alpha/255f);
36        worstCase = ColorUtils.setAlphaComponent(worstCase, 255);
37        double contrast = ColorUtils.calculateContrast(Color.WHITE, worstCase);
38        assertTrue("Blended color should satisfy contrast", contrast >= 4.5);
39
40    }
41}
42