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Move Random List Element examples

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This commit is contained in:
Grzegorz Piwowarek
2016-10-23 21:22:07 +02:00
parent d9c3a9d9cd
commit ce0cb0c375
2 changed files with 2 additions and 1 deletions
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71
core-java-8/src/test/java/com/baeldung/RandomListElementTest.java
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@@ -1,71 +0,0 @@
package com.baeldung;
import com.google.common.collect.Lists;
import org.junit.Test;
import java.util.*;
import java.util.concurrent.ThreadLocalRandom;
public class RandomListElementTest {
@Test
public void givenList_whenRandomIndexChosen_shouldReturnARandomElementUsingRandom() {
List<Integer> givenList = Lists.newArrayList(1, 2, 3);
Random rand = new Random();
givenList.get(rand.nextInt(givenList.size()));
}
@Test
public void givenList_whenRandomIndexChosen_shouldReturnARandomElementUsingMathRandom() {
List<Integer> givenList = Lists.newArrayList(1, 2, 3);
givenList.get((int)(Math.random() * givenList.size()));
}
@Test
public void givenList_whenNumberElementsChosen_shouldReturnRandomElementsRepeat() {
Random rand = new Random();
List<String> givenList = Lists.newArrayList("one", "two", "three", "four");
int numberOfElements = 2;
for (int i = 0; i < numberOfElements; i++) {
int randomIndex = rand.nextInt(givenList.size());
givenList.get(randomIndex);
}
}
@Test
public void givenList_whenNumberElementsChosen_shouldReturnRandomElementsNoRepeat() {
Random rand = new Random();
List<String> givenList = Lists.newArrayList("one", "two", "three", "four");
int numberOfElements = 2;
for (int i = 0; i < numberOfElements; i++) {
int randomIndex = rand.nextInt(givenList.size());
givenList.get(randomIndex);
givenList.remove(randomIndex);
}
}
@Test
public void givenList_whenSeriesLengthChosen_shouldReturnRandomSeries() {
List<Integer> givenList = Lists.newArrayList(1, 2, 3, 4, 5, 6);
Collections.shuffle(givenList);
int randomSeriesLength = 3;
givenList.subList(0, randomSeriesLength - 1);
}
@Test
public void givenList_whenRandomIndexChosen_shouldReturnElementThreadSafely() {
List<Integer> givenList = Lists.newArrayList(1, 2, 3, 4, 5, 6);
int randomIndex = ThreadLocalRandom.current().nextInt(10) % givenList.size();
givenList.get(randomIndex);
}
}