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BAEL-3919 (#9072) 

BAEL-3919 code
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vatsalgosar 2020-04-17 01:10:04 +05:30 committed by GitHub
parent 1239da8e6d
commit 2815700ebf
1 changed files with 39 additions and 0 deletions
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core-java-modules/core-java-collections-maps-3/src/test/java/com/baeldung/map/computeifabsent/ComputeIfAbsentUnitTest.java Normal file
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package com.baeldung.map.computeifabsent;
import org.junit.Test;
import java.util.HashMap;
import java.util.Map;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;
public class ComputeIfAbsentUnitTest {
@Test
public void whenKeyIsPresent_thenFetchTheValue() {
Map<String, Integer> stringLength = new HashMap<>();
stringLength.put("John", 5);
assertEquals((long)stringLength.computeIfAbsent("John", s -> s.length()), 5);
}
@Test
public void whenKeyIsNotPresent_thenComputeTheValueUsingMappingFunctionAndStore() {
Map<String, Integer> stringLength = new HashMap<>();
assertEquals((long)stringLength.computeIfAbsent("John", s -> s.length()), 4);
assertEquals((long)stringLength.get("John"), 4);
}
@Test
public void whenMappingFunctionReturnsNull_thenDoNotRecordMapping() {
Map<String, Integer> stringLength = new HashMap<>();
assertEquals(stringLength.computeIfAbsent("John", s -> null), null);
assertNull(stringLength.get("John"));
}
@Test(expected = RuntimeException.class)
public void whenMappingFunctionThrowsException_thenExceptionIsRethrown() {
Map<String, Integer> stringLength = new HashMap<>();
stringLength.computeIfAbsent("John", s -> {throw new RuntimeException();});
}
}