added examples about how to reverse a string in java (#7219)

This commit is contained in:
Catalin Burcea
2019-07-01 14:16:19 +03:00
committed by maibin
parent 1318804764
commit c79bc22668
2 changed files with 126 additions and 0 deletions

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@@ -0,0 +1,70 @@
package com.baeldung.string.reverse;
import org.apache.commons.lang3.StringUtils;
import org.junit.Test;
import static org.junit.Assert.assertEquals;
public class ReverseStringExamplesUnitTest {
private static final String STRING_INPUT = "cat";
private static final String STRING_INPUT_REVERSED = "tac";
private static final String SENTENCE = "The quick brown fox jumps over the lazy dog";
private static final String REVERSED_WORDS_SENTENCE = "dog lazy the over jumps fox brown quick The";
@Test
public void whenReverseIsCalled_ThenCorrectStringIsReturned() {
String reversed = ReverseStringExamples.reverse(STRING_INPUT);
String reversedNull = ReverseStringExamples.reverse(null);
String reversedEmpty = ReverseStringExamples.reverse(StringUtils.EMPTY);
assertEquals(STRING_INPUT_REVERSED, reversed);
assertEquals(null, reversedNull);
assertEquals(StringUtils.EMPTY, reversedEmpty);
}
@Test
public void whenReverseUsingStringBuilderIsCalled_ThenCorrectStringIsReturned() throws Exception {
String reversed = ReverseStringExamples.reverseUsingStringBuilder(STRING_INPUT);
String reversedNull = ReverseStringExamples.reverseUsingStringBuilder(null);
String reversedEmpty = ReverseStringExamples.reverseUsingStringBuilder(StringUtils.EMPTY);
assertEquals(STRING_INPUT_REVERSED, reversed);
assertEquals(null, reversedNull);
assertEquals(StringUtils.EMPTY, reversedEmpty);
}
@Test
public void whenReverseUsingApacheCommonsIsCalled_ThenCorrectStringIsReturned() throws Exception {
String reversed = ReverseStringExamples.reverseUsingApacheCommons(STRING_INPUT);
String reversedNull = ReverseStringExamples.reverseUsingApacheCommons(null);
String reversedEmpty = ReverseStringExamples.reverseUsingApacheCommons(StringUtils.EMPTY);
assertEquals(STRING_INPUT_REVERSED, reversed);
assertEquals(null, reversedNull);
assertEquals(StringUtils.EMPTY, reversedEmpty);
}
@Test
public void whenReverseTheOrderOfWordsIsCalled_ThenCorrectStringIsReturned() {
String reversed = ReverseStringExamples.reverseTheOrderOfWords(SENTENCE);
String reversedNull = ReverseStringExamples.reverseTheOrderOfWords(null);
String reversedEmpty = ReverseStringExamples.reverseTheOrderOfWords(StringUtils.EMPTY);
assertEquals(REVERSED_WORDS_SENTENCE, reversed);
assertEquals(null, reversedNull);
assertEquals(StringUtils.EMPTY, reversedEmpty);
}
@Test
public void whenReverseTheOrderOfWordsUsingApacheCommonsIsCalled_ThenCorrectStringIsReturned() {
String reversed = ReverseStringExamples.reverseTheOrderOfWordsUsingApacheCommons(SENTENCE);
String reversedNull = ReverseStringExamples.reverseTheOrderOfWordsUsingApacheCommons(null);
String reversedEmpty = ReverseStringExamples.reverseTheOrderOfWordsUsingApacheCommons(StringUtils.EMPTY);
assertEquals(REVERSED_WORDS_SENTENCE, reversed);
assertEquals(null, reversedNull);
assertEquals(StringUtils.EMPTY, reversedEmpty);
}
}