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[map-KV-to-list] Get Values and Keys as ArralyLists From a HashMap (#14615)

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Kai Yuan 2023-08-18 21:48:48 +02:00 committed by GitHub
parent 8502670140
commit 16080930fa
1 changed files with 72 additions and 0 deletions
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core-java-modules/core-java-collections-maps-3/src/test/java/com/baeldung/map/hashmap/kvtolist/MapKeysValuesToListUnitTest.java Normal file
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package com.baeldung.map.hashmap.kvtolist;
import static org.assertj.core.api.Assertions.assertThat;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.junit.jupiter.api.Test;
public class MapKeysValuesToListUnitTest {
private static final HashMap<String, String> DEV_MAP;
static {
DEV_MAP = new HashMap<>();
DEV_MAP.put("Kent", "Linux");
DEV_MAP.put("Eric", "MacOS");
DEV_MAP.put("Kevin", "Windows");
DEV_MAP.put("Michal", "MacOS");
DEV_MAP.put("Saajan", "Linux");
}
@Test
void whenUsingKeySet_thenGetExpectedResult() {
List<String> keyList = new ArrayList<>(DEV_MAP.keySet());
// this assertion may fail, since hashMap doesn't preserve the insertion order
// assertEquals(Lists.newArrayList("Kent", "Eric", "Kevin", "Michal", "Saajan"), keyList);
assertThat(keyList).containsExactlyInAnyOrder("Kent", "Eric", "Kevin", "Michal", "Saajan");
}
@Test
void whenUsingValues_thenGetExpectedResult() {
List<String> valueList = new ArrayList<>(DEV_MAP.values());
assertThat(valueList).containsExactlyInAnyOrder("Linux", "MacOS", "Windows", "MacOS", "Linux");
}
@Test
void whenLoopingEntries_thenGetExpectedResult() {
List<String> keyList = new ArrayList<>();
List<String> valueList = new ArrayList<>();
for (Map.Entry<String, String> entry : DEV_MAP.entrySet()) {
keyList.add(entry.getKey());
valueList.add(entry.getValue());
}
assertKeyAndValueList(keyList, valueList);
}
@Test
void whenUsingForEach_thenGetExpectedResult() {
List<String> keyList = new ArrayList<>();
List<String> valueList = new ArrayList<>();
DEV_MAP.forEach((k, v) -> {
keyList.add(k);
valueList.add(v);
});
assertKeyAndValueList(keyList, valueList);
}
private void assertKeyAndValueList(List<String> keyList, List<String> valueList) {
assertThat(keyList).containsExactlyInAnyOrder("Kent", "Eric", "Kevin", "Michal", "Saajan");
assertThat(valueList).containsExactlyInAnyOrder("Linux", "MacOS", "Windows", "MacOS", "Linux");
for (int i = 0; i < keyList.size(); i++) {
assertThat(DEV_MAP).containsEntry(keyList.get(i), valueList.get(i));
}
}
}