这是indexloc提供的服务，不要输入任何密码
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Merged
merged 3 commits into from
Apr 26, 2024
Merged

Bael 7882 #16500

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75e49be
BAEL-7882: Test for finding the index of the smallest number
eukovko Apr 25, 2024
f0efadb
BAEL-7882: Added new test cases
eukovko Apr 26, 2024
54d369b
BAEL-7882: Added an example with Apache Commons
eukovko Apr 26, 2024
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8 changes: 8 additions & 0 deletions core-java-modules/core-java-arrays-operations-basic-2/pom.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -13,4 +13,12 @@
<version>0.0.1-SNAPSHOT</version>
</parent>

<dependencies>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-lang3</artifactId>
<version>3.14.0</version>
</dependency>
</dependencies>

</project>
132 changes: 132 additions & 0 deletions ...-basic-2/src/test/java/com/baeldung/array/smallestindex/SmallestElementIndexUnitTest.java
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@@ -0,0 +1,132 @@
package com.baeldung.array.smallestindex;

import static org.assertj.core.api.Assertions.assertThat;

import java.util.Arrays;
import java.util.List;
import java.util.stream.Collectors;
import java.util.stream.IntStream;
import java.util.stream.Stream;
import org.apache.commons.lang3.ArrayUtils;
import org.junit.jupiter.params.ParameterizedTest;
import org.junit.jupiter.params.provider.Arguments;
import org.junit.jupiter.params.provider.MethodSource;

class SmallestElementIndexUnitTest {

@ParameterizedTest
@MethodSource("primitiveProvider")
void givenArray_whenUsingForLoop_thenGetCorrectResult(int[] array, int expectedIndex) {
int minValue = Integer.MAX_VALUE;
int minIndex = -1;
for (int i = 0; i < array.length; i++) {
if (array[i] < minValue) {
minValue = array[i];
minIndex = i;
}
}
assertThat(minIndex).isEqualTo(expectedIndex);
}

@ParameterizedTest
@MethodSource("primitiveProvider")
void givenArray_whenUsingForLoopAndLookForIndex_thenGetCorrectResult(int[] array, int expectedIndex) {
int minValue = Integer.MAX_VALUE;
for (int number : array) {
if (number < minValue) {
minValue = number;
}
}
int minIndex = -1;
for (int i = 0; i < array.length; i++) {
if (array[i] == minValue) {
minIndex = i;
break;
}
}
assertThat(minIndex).isEqualTo(expectedIndex);
}

@ParameterizedTest
@MethodSource("primitiveProvider")
void givenArray_whenUsingIntStreamAndLookForIndex_thenGetCorrectResult(int[] array, int expectedIndex) {
int minValue = Arrays.stream(array).min().orElse(Integer.MAX_VALUE);
int minIndex = -1;
for (int i = 0; i < array.length; i++) {
if (array[i] == minValue) {
minIndex = i;
break;
}
}
assertThat(minIndex).isEqualTo(expectedIndex);
}

@ParameterizedTest
@MethodSource("primitiveProvider")
void givenArray_whenUsingIntStreamAndLookForIndexWithIntStream_thenGetCorrectResult(int[] array, int expectedIndex) {
int minValue = Arrays.stream(array).min().orElse(Integer.MAX_VALUE);
int minIndex = IntStream.range(0, array.length)
.filter(index -> array[index] == minValue)
.findFirst().orElse(-1);
assertThat(minIndex).isEqualTo(expectedIndex);
}

@ParameterizedTest
@MethodSource("primitiveProvider")
void givenArray_whenUsingIntStreamAndLookForIndexWithArrayUtils_thenGetCorrectResult(int[] array, int expectedIndex) {
int minValue = Arrays.stream(array).min().orElse(Integer.MAX_VALUE);
int minIndex = ArrayUtils.indexOf(array, minValue);
assertThat(minIndex).isEqualTo(expectedIndex);
}

@ParameterizedTest
@MethodSource("referenceTypesProvider")
void givenArray_whenUsingReduce_thenGetCorrectResult(Integer[] array, int expectedIndex) {
int minValue = Arrays.stream(array).reduce(Integer.MAX_VALUE, Integer::min);
int minIndex = ArrayUtils.indexOf(array, minValue);
assertThat(minIndex).isEqualTo(expectedIndex);
}

@ParameterizedTest
@MethodSource("referenceTypesProvider")
void givenArray_whenUsingReduceAndList_thenGetCorrectResult(Integer[] array, int expectedIndex) {
List<Integer> list = Arrays.asList(array);
int minValue = list.stream().reduce(Integer.MAX_VALUE, Integer::min);
int index = list.indexOf(minValue);
assertThat(index).isEqualTo(expectedIndex);
}

@ParameterizedTest
@MethodSource("primitiveProvider")
void givenArray_whenUsingReduceWithRange_thenGetCorrectResult(int[] array, int expectedIndex) {
int index = IntStream.range(0, array.length)
.reduce((a, b) -> array[a] <= array[b] ? a : b)
.orElse(-1);
assertThat(index).isEqualTo(expectedIndex);
}

@ParameterizedTest
@MethodSource("primitiveProvider")
void givenArray_whenUsingPrimitiveStreams_thenGetCorrectResult(int[] array, int expectedIndex) {
List<Integer> list = Arrays.stream(array).boxed().collect(Collectors.toList());
int minValue = Arrays.stream(array).min().orElse(Integer.MAX_VALUE);
int index = list.indexOf(minValue);
assertThat(index).isEqualTo(expectedIndex);
}

static Stream<Arguments> primitiveProvider() {
return Stream.of(
Arguments.of(new int[]{585, 190, 201, 82, 332}, 3),
Arguments.of(new int[]{1, 1, 1}, 0),
Arguments.of(new int[]{}, -1)
);
}

static Stream<Arguments> referenceTypesProvider() {
return Stream.of(
Arguments.of(new Integer[]{585, 190, 201, 82, 332}, 3),
Arguments.of(new Integer[]{1, 1, 1}, 0),
Arguments.of(new Integer[]{}, -1)
);
}
}