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/*
* 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.assertArrayEquals;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.fail;
import android.os.Build;
import androidx.test.filters.SmallTest;
import com.android.testutils.DevSdkIgnoreRule;
import com.android.testutils.DevSdkIgnoreRunner;
import org.junit.Test;
import org.junit.runner.RunWith;
@SmallTest
@RunWith(DevSdkIgnoreRunner.class)
@DevSdkIgnoreRule.IgnoreUpTo(Build.VERSION_CODES.R)
public class RingBufferTest {
@Test
public void testEmptyRingBuffer() {
RingBuffer<String> buffer = new RingBuffer<>(String.class, 100);
assertArrayEquals(new String[0], buffer.toArray());
}
@Test
public void testIncorrectConstructorArguments() {
try {
RingBuffer<String> buffer = new RingBuffer<>(String.class, -10);
fail("Should not be able to create a negative capacity RingBuffer");
} catch (IllegalArgumentException expected) {
}
try {
RingBuffer<String> 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<String> 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"};
assertArrayEquals(expected, buffer.toArray());
}
@Test
public void testRingBufferWithCapacity1() {
RingBuffer<String> buffer = new RingBuffer<>(String.class, 1);
buffer.append("a");
assertArrayEquals(new String[]{"a"}, buffer.toArray());
buffer.append("b");
assertArrayEquals(new String[]{"b"}, buffer.toArray());
buffer.append("c");
assertArrayEquals(new String[]{"c"}, buffer.toArray());
buffer.append("d");
assertArrayEquals(new String[]{"d"}, buffer.toArray());
buffer.append("e");
assertArrayEquals(new String[]{"e"}, buffer.toArray());
}
@Test
public void testRingBufferWithWrapping() {
int capacity = 100;
RingBuffer<String> 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"};
assertArrayEquals(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";
}
assertArrayEquals(expected2, buffer.toArray());
buffer.append("x");
expected2[firstIndex] = "x";
assertArrayEquals(expected2, buffer.toArray());
for (int i = 0; i < 10; i++) {
for (String s : expected2) {
buffer.append(s);
}
}
assertArrayEquals(expected2, buffer.toArray());
buffer.append("a");
expected2[lastIndex] = "a";
assertArrayEquals(expected2, buffer.toArray());
}
@Test
public void testGetNextSlot() {
int capacity = 100;
RingBuffer<DummyClass1> buffer = new RingBuffer<>(DummyClass1.class, capacity);
final DummyClass1[] actual = new DummyClass1[capacity];
final DummyClass1[] expected = new DummyClass1[capacity];
for (int i = 0; i < capacity; ++i) {
final DummyClass1 obj = buffer.getNextSlot();
obj.x = capacity * i;
actual[i] = obj;
expected[i] = new DummyClass1();
expected[i].x = capacity * i;
}
assertArrayEquals(expected, buffer.toArray());
for (int i = 0; i < capacity; ++i) {
if (actual[i] != buffer.getNextSlot()) {
fail("getNextSlot() should re-use objects if available");
}
}
RingBuffer<DummyClass2> buffer2 = new RingBuffer<>(DummyClass2.class, capacity);
assertNull("getNextSlot() should return null if the object can't be initiated "
+ "(No nullary constructor)", buffer2.getNextSlot());
RingBuffer<DummyClass3> buffer3 = new RingBuffer<>(DummyClass3.class, capacity);
assertNull("getNextSlot() should return null if the object can't be initiated "
+ "(Inaccessible class)", buffer3.getNextSlot());
}
public static final class DummyClass1 {
int x;
public boolean equals(Object o) {
if (o instanceof DummyClass1) {
final DummyClass1 other = (DummyClass1) o;
return other.x == this.x;
}
return false;
}
}
public static final class DummyClass2 {
public DummyClass2(int x) {}
}
private static final class DummyClass3 {}
}
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