From b04e68e10b81b63113b9ef927f1d2fb1e66ecba2 Mon Sep 17 00:00:00 2001
From: Teica <matea.pejcinovic@gmail.com>
Date: Sat, 9 Oct 2021 04:54:31 +0200
Subject: [PATCH] BAEL-5161 Added tests for updating the value of a key in a
HashMap (#11300)
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Co-authored-by: Matea Pejčinović <matea.pejcinovic@intellexi.hr>
---
.../map/hashing/HashMapUpdateUnitTest.java | 126 ++++++++++++++++++
1 file changed, 126 insertions(+)
create mode 100644 java-collections-maps-3/src/test/java/com/baeldung/map/hashing/HashMapUpdateUnitTest.java
diff --git a/java-collections-maps-3/src/test/java/com/baeldung/map/hashing/HashMapUpdateUnitTest.java b/java-collections-maps-3/src/test/java/com/baeldung/map/hashing/HashMapUpdateUnitTest.java
new file mode 100644
index 0000000000..4659434d7b
--- /dev/null
+++ b/java-collections-maps-3/src/test/java/com/baeldung/map/hashing/HashMapUpdateUnitTest.java
@@ -0,0 +1,126 @@
+package com.baeldung.map.hashing;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInstance;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.function.BiFunction;
+
+@TestInstance(TestInstance.Lifecycle.PER_CLASS)
+public class HashMapUpdateUnitTest {
+
+ Map<String, Double> fruitMap = new HashMap<>();
+
+ @BeforeAll
+ void setup() {
+ fruitMap.put("apple", 2.45);
+ fruitMap.put("grapes", 1.22);
+ }
+
+ @Test
+ public void givenFruitMap_whenPuttingAList_thenHashMapUpdatesAndInsertsValues() {
+ Double newValue = 2.11;
+ fruitMap.put("apple", newValue);
+ fruitMap.put("orange", newValue);
+ Assertions.assertEquals(newValue, fruitMap.get("apple"));
+ Assertions.assertTrue(fruitMap.containsKey("orange"));
+ Assertions.assertEquals(newValue, fruitMap.get("orange"));
+ }
+
+ @Test
+ public void givenFruitMap_whenKeyExists_thenValuesUpdated() {
+ double newValue = 2.31;
+ if (fruitMap.containsKey("apple")) {
+ fruitMap.put("apple", newValue);
+ }
+ Assertions.assertEquals(Double.valueOf(newValue), fruitMap.get("apple"));
+ }
+
+ @Test
+ public void givenFruitMap_whenReplacingOldValue_thenNewValueSet() {
+ double newPrice = 3.22;
+ Double applePrice = fruitMap.get("apple");
+ Double oldValue = fruitMap.replace("apple", newPrice);
+ Assertions.assertNotNull(oldValue);
+ Assertions.assertEquals(oldValue, applePrice);
+ Assertions.assertEquals(Double.valueOf(newPrice), fruitMap.get("apple"));
+ }
+
+ @Test
+ public void givenFruitMap_whenReplacingWithRealOldValue_thenNewValueSet() {
+ double newPrice = 3.22;
+ Double applePrice = fruitMap.get("apple");
+ boolean isUpdated = fruitMap.replace("apple", applePrice, newPrice);
+ Assertions.assertTrue(isUpdated);
+ }
+
+ @Test
+ public void givenFruitMap_whenReplacingWithWrongOldValue_thenNewValueNotSet() {
+ double newPrice = 3.22;
+ boolean isUpdated = fruitMap.replace("apple", Double.valueOf(0), newPrice);
+ Assertions.assertFalse(isUpdated);
+ }
+
+ @Test
+ public void givenFruitMap_whenGetOrDefaultUsedWithPut_thenNewEntriesAdded() {
+ fruitMap.put("plum", fruitMap.getOrDefault("plum", 2.41));
+ Assertions.assertTrue(fruitMap.containsKey("plum"));
+ Assertions.assertEquals(Double.valueOf(2.41), fruitMap.get("plum"));
+ }
+
+ @Test
+ public void givenFruitMap_whenPutIfAbsentUsed_thenNewEntriesAdded() {
+ double newValue = 1.78;
+ fruitMap.putIfAbsent("apple", newValue);
+ fruitMap.putIfAbsent("pear", newValue);
+ Assertions.assertTrue(fruitMap.containsKey("pear"));
+ Assertions.assertNotEquals(Double.valueOf(newValue), fruitMap.get("apple"));
+ Assertions.assertEquals(Double.valueOf(newValue), fruitMap.get("pear"));
+ }
+
+ @Test
+ public void givenFruitMap_whenComputeUsed_thenValueUpdated() {
+ double oldPrice = fruitMap.get("apple");
+ BiFunction<Double, Integer, Double> powFunction = (x1, x2) -> Math.pow(x1, x2);
+ fruitMap.compute(
+ "apple", (k, v) -> powFunction.apply(v, 2));
+ Assertions.assertEquals(
+ Double.valueOf(Math.pow(oldPrice, 2)), fruitMap.get("apple"));
+ Assertions.assertThrows(
+ NullPointerException.class, () -> fruitMap.compute("blueberry", (k, v) -> powFunction.apply(v, 2)));
+ }
+
+ @Test
+ public void givenFruitMap_whenComputeIfAbsentUsed_thenNewEntriesAdded() {
+ fruitMap.computeIfAbsent(
+ "lemon", k -> Double.valueOf(k.length()));
+ Assertions.assertTrue(fruitMap.containsKey("lemon"));
+ Assertions.assertEquals(Double.valueOf("lemon".length()), fruitMap.get("lemon"));
+ }
+
+ @Test
+ public void givenFruitMap_whenComputeIfPresentUsed_thenValuesUpdated() {
+ Double oldAppleValue = fruitMap.get("apple");
+ BiFunction<Double, Integer, Double> powFunction = (x1, x2) -> Math.pow(x1, x2);
+ fruitMap.computeIfPresent(
+ "apple", (k, v) -> powFunction.apply(v, 2));
+ Assertions.assertEquals(Double.valueOf(Math.pow(oldAppleValue, 2)), fruitMap.get("apple"));
+ }
+
+ @Test
+ public void givenFruitMap_whenMergeUsed_thenNewEntriesAdded() {
+ double defaultValue = 1.25;
+ BiFunction<Double, Integer, Double> powFunction = (x1, x2) -> Math.pow(x1, x2);
+ fruitMap.merge(
+ "apple", defaultValue, (k, v) -> powFunction.apply(v, 2));
+ fruitMap.merge(
+ "strawberry", defaultValue, (k, v) -> powFunction.apply(v, 2));
+ Assertions.assertTrue(fruitMap.containsKey("strawberry"));
+ Assertions.assertEquals(Double.valueOf(defaultValue), fruitMap.get("strawberry"));
+ Assertions.assertEquals(Double.valueOf(Math.pow(defaultValue, 2)), fruitMap.get("apple"));
+ }
+
+}