diff --git a/tests/net/java/com/android/internal/util/RingBufferTest.java b/tests/net/java/com/android/internal/util/RingBufferTest.java new file mode 100644 index 0000000000..7a23443172 --- /dev/null +++ b/tests/net/java/com/android/internal/util/RingBufferTest.java @@ -0,0 +1,145 @@ +/* + * Copyright (C) 2017 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.internal.util; + +import static org.junit.Assert.assertEquals; +import static org.junit.Assert.fail; + +import android.support.test.filters.SmallTest; +import android.support.test.runner.AndroidJUnit4; + +import org.junit.Test; +import org.junit.runner.RunWith; +import java.util.Arrays; +import java.util.Objects; + + +@SmallTest +@RunWith(AndroidJUnit4.class) +public class RingBufferTest { + + @Test + public void testEmptyRingBuffer() { + RingBuffer buffer = new RingBuffer<>(String.class, 100); + + assertArraysEqual(new String[0], buffer.toArray()); + } + + @Test + public void testIncorrectConstructorArguments() { + try { + RingBuffer buffer = new RingBuffer<>(String.class, -10); + fail("Should not be able to create a negative capacity RingBuffer"); + } catch (IllegalArgumentException expected) { + } + + try { + RingBuffer buffer = new RingBuffer<>(String.class, 0); + fail("Should not be able to create a 0 capacity RingBuffer"); + } catch (IllegalArgumentException expected) { + } + } + + @Test + public void testRingBufferWithNoWrapping() { + RingBuffer buffer = new RingBuffer<>(String.class, 100); + + buffer.append("a"); + buffer.append("b"); + buffer.append("c"); + buffer.append("d"); + buffer.append("e"); + + String[] expected = {"a", "b", "c", "d", "e"}; + assertArraysEqual(expected, buffer.toArray()); + } + + @Test + public void testRingBufferWithCapacity1() { + RingBuffer buffer = new RingBuffer<>(String.class, 1); + + buffer.append("a"); + assertArraysEqual(new String[]{"a"}, buffer.toArray()); + + buffer.append("b"); + assertArraysEqual(new String[]{"b"}, buffer.toArray()); + + buffer.append("c"); + assertArraysEqual(new String[]{"c"}, buffer.toArray()); + + buffer.append("d"); + assertArraysEqual(new String[]{"d"}, buffer.toArray()); + + buffer.append("e"); + assertArraysEqual(new String[]{"e"}, buffer.toArray()); + } + + @Test + public void testRingBufferWithWrapping() { + int capacity = 100; + RingBuffer buffer = new RingBuffer<>(String.class, capacity); + + buffer.append("a"); + buffer.append("b"); + buffer.append("c"); + buffer.append("d"); + buffer.append("e"); + + String[] expected1 = {"a", "b", "c", "d", "e"}; + assertArraysEqual(expected1, buffer.toArray()); + + String[] expected2 = new String[capacity]; + int firstIndex = 0; + int lastIndex = capacity - 1; + + expected2[firstIndex] = "e"; + for (int i = 1; i < capacity; i++) { + buffer.append("x"); + expected2[i] = "x"; + } + assertArraysEqual(expected2, buffer.toArray()); + + buffer.append("x"); + expected2[firstIndex] = "x"; + assertArraysEqual(expected2, buffer.toArray()); + + for (int i = 0; i < 10; i++) { + for (String s : expected2) { + buffer.append(s); + } + } + assertArraysEqual(expected2, buffer.toArray()); + + buffer.append("a"); + expected2[lastIndex] = "a"; + assertArraysEqual(expected2, buffer.toArray()); + } + + static void assertArraysEqual(T[] expected, T[] got) { + if (expected.length != got.length) { + fail(Arrays.toString(expected) + " and " + Arrays.toString(got) + + " did not have the same length"); + } + + for (int i = 0; i < expected.length; i++) { + if (!Objects.equals(expected[i], got[i])) { + fail(Arrays.toString(expected) + " and " + Arrays.toString(got) + + " were not equal"); + } + } + } +}