1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 package org.apache.commons.rng.core.source32; 18 19 import org.junit.Assert; 20 import org.junit.Test; 21 22 /** 23 * The tests the caching of calls to {@link IntProvider#nextInt()} are used as 24 * the source for {@link IntProvider#nextInt()} and 25 * {@link IntProvider#nextBoolean()}. 26 */ 27 public class IntProviderTest { 28 /** 29 * A simple class to flip the bits in a number as the source for 30 * {@link IntProvider#next()}. 31 */ 32 static final class FlipIntProvider extends IntProvider { 33 /** The value. */ 34 private int value; 35 36 /** 37 * @param value the value 38 */ 39 public FlipIntProvider(int value) { 40 // Flip the bits so the first call to next() returns to the same state 41 this.value = ~value; 42 } 43 44 @Override 45 public int next() { 46 // Flip the bits 47 value = ~value; 48 return value; 49 } 50 } 51 52 /** 53 * This test ensures that the call to {@link IntProvider#nextBoolean()} returns 54 * each of the bits from a call to {@link IntProvider#nextInt()}. 55 * 56 * <p>The order should be from the least-significant bit. 57 */ 58 @Test 59 public void testNextBoolean() { 60 for (int i = 0; i < Integer.SIZE; i++) { 61 // Set only a single bit in the source 62 final int value = 1 << i; 63 final IntProvider provider = new FlipIntProvider(value); 64 // Test the result for a single pass over the long 65 for (int j = 0; j < Integer.SIZE; j++) { 66 final boolean expected = (i == j); 67 Assert.assertEquals("Pass 1, bit " + j, expected, provider.nextBoolean()); 68 } 69 // The second pass should use the opposite bits 70 for (int j = 0; j < Integer.SIZE; j++) { 71 final boolean expected = (i != j); 72 Assert.assertEquals("Pass 2, bit " + j, expected, provider.nextBoolean()); 73 } 74 } 75 } 76 }