From bdcc961542282c5411d2ad7e6196dccccb9e075f Mon Sep 17 00:00:00 2001 From: ramansahasi Date: Thu, 3 Jan 2019 20:19:51 +0530 Subject: [PATCH] BAEL-2392_Java_String_interview_questions second commit (#6064) --- .../string/interview/LocaleUnitTest.java | 19 +++++++++++ .../interview/StringAnagramUnitTest.java | 29 +++++++++++++++++ .../interview/StringChangeCaseUnitTest.java | 20 ++++++++++++ .../StringCountOccurrencesUnitTest.java | 28 ++++++++++++++++ .../interview/StringFormatUnitTest.java | 14 ++++++++ .../interview/StringInternUnitTest.java | 17 ++++++++++ .../interview/StringJoinerUnitTest.java | 18 +++++++++++ .../interview/StringPalindromeUnitTest.java | 29 +++++++++++++++++ .../interview/StringReverseUnitTest.java | 13 ++++++++ .../string/interview/StringSplitUnitTest.java | 32 +++++++++++++++++++ .../interview/StringToByteArrayUnitTest.java | 24 ++++++++++++++ .../interview/StringToCharArrayUnitTest.java | 17 ++++++++++ .../interview/StringToIntegerUnitTest.java | 15 +++++++++ 13 files changed, 275 insertions(+) create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/LocaleUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringAnagramUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringChangeCaseUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringCountOccurrencesUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringFormatUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringInternUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringJoinerUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringPalindromeUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringReverseUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringSplitUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringToByteArrayUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringToCharArrayUnitTest.java create mode 100644 java-strings/src/test/java/com/baeldung/string/interview/StringToIntegerUnitTest.java diff --git a/java-strings/src/test/java/com/baeldung/string/interview/LocaleUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/LocaleUnitTest.java new file mode 100644 index 0000000000..1d221056fd --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/LocaleUnitTest.java @@ -0,0 +1,19 @@ +package com.baeldung.string.interview; + +import java.math.BigDecimal; +import java.text.NumberFormat; +import java.util.Locale; +import static org.junit.Assert.assertEquals; + +import org.junit.Test; + +public class LocaleUnitTest { + @Test + public void whenUsingLocal_thenCorrectResultsForDifferentLocale() { + Locale usLocale = Locale.US; + BigDecimal number = new BigDecimal(102_300.456d); + + NumberFormat usNumberFormat = NumberFormat.getCurrencyInstance(usLocale); + assertEquals(usNumberFormat.format(number), "$102,300.46"); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringAnagramUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringAnagramUnitTest.java new file mode 100644 index 0000000000..aadfade737 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringAnagramUnitTest.java @@ -0,0 +1,29 @@ +package com.baeldung.string.interview; + +import static org.assertj.core.api.Assertions.assertThat; + +import java.util.Arrays; + +import org.junit.Test; + +public class StringAnagramUnitTest { + public boolean isAnagram(String s1, String s2) { + if(s1.length() != s2.length()) + return false; + + char[] arr1 = s1.toCharArray(); + char[] arr2 = s2.toCharArray(); + + Arrays.sort(arr1); + Arrays.sort(arr2); + + return Arrays.equals(arr1, arr2); + } + + @Test + public void whenTestAnagrams_thenTestingCorrectly() { + assertThat(isAnagram("car", "arc")).isTrue(); + assertThat(isAnagram("west", "stew")).isTrue(); + assertThat(isAnagram("west", "east")).isFalse(); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringChangeCaseUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringChangeCaseUnitTest.java new file mode 100644 index 0000000000..2c7ec500fe --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringChangeCaseUnitTest.java @@ -0,0 +1,20 @@ +package com.baeldung.string.interview; + +import static org.junit.Assert.assertEquals; + +import org.junit.Test; + +public class StringChangeCaseUnitTest { + @Test + public void givenString_whenChangingToUppercase_thenCaseChanged() { + String s = "Welcome to Baeldung!"; + assertEquals("WELCOME TO BAELDUNG!", s.toUpperCase()); + } + + + @Test + public void givenString_whenChangingToLowerrcase_thenCaseChanged() { + String s = "Welcome to Baeldung!"; + assertEquals("welcome to baeldung!", s.toLowerCase()); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringCountOccurrencesUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringCountOccurrencesUnitTest.java new file mode 100644 index 0000000000..6c17643ac8 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringCountOccurrencesUnitTest.java @@ -0,0 +1,28 @@ +package com.baeldung.string.interview; + +import static org.junit.Assert.assertEquals; + +import org.junit.Test; + +public class StringCountOccurrencesUnitTest { + public int countOccurrences(String s, char c) { + int count = 0; + for (int i = 0; i < s.length(); i++) { + if (s.charAt(i) == c) { + count++; + } + } + return count; + } + + @Test + public void givenString_whenCountingFrequencyOfChar_thenCountCorrect() { + assertEquals(3, countOccurrences("united states", 't')); + } + + public void givenString_whenUsingJava8_thenCountingOfCharCorrect() { + String str = "united states"; + long count = str.chars().filter(ch -> (char)ch == 't').count(); + assertEquals(3, count); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringFormatUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringFormatUnitTest.java new file mode 100644 index 0000000000..787017791c --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringFormatUnitTest.java @@ -0,0 +1,14 @@ +package com.baeldung.string.interview; + +import static org.junit.Assert.assertEquals; + +import org.junit.Test; + +public class StringFormatUnitTest { + @Test + public void givenString_whenUsingStringFormat_thenStringFormatted() { + String title = "Baeldung"; + String formatted = String.format("Title is %s", title); + assertEquals(formatted, "Title is Baeldung"); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringInternUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringInternUnitTest.java new file mode 100644 index 0000000000..c5bffb7573 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringInternUnitTest.java @@ -0,0 +1,17 @@ +package com.baeldung.string.interview; + +import static org.assertj.core.api.Assertions.assertThat; + +import org.junit.Test; + +public class StringInternUnitTest { + @Test + public void whenCallingStringIntern_thenStringsInterned() { + String s1 = "Baeldung"; + String s2 = new String("Baeldung"); + String s3 = new String("Baeldung").intern(); + + assertThat(s1 == s2).isFalse(); + assertThat(s1 == s3).isTrue(); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringJoinerUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringJoinerUnitTest.java new file mode 100644 index 0000000000..d44c7478e4 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringJoinerUnitTest.java @@ -0,0 +1,18 @@ +package com.baeldung.string.interview; + +import java.util.StringJoiner; +import static org.junit.Assert.assertEquals; + +import org.junit.Test; + +public class StringJoinerUnitTest { + @Test + public void whenUsingStringJoiner_thenStringsJoined() { + StringJoiner joiner = new StringJoiner(",", "[", "]"); + joiner.add("Red") + .add("Green") + .add("Blue"); + + assertEquals(joiner.toString(), "[Red,Green,Blue]"); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringPalindromeUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringPalindromeUnitTest.java new file mode 100644 index 0000000000..79ed14cd99 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringPalindromeUnitTest.java @@ -0,0 +1,29 @@ +package com.baeldung.string.interview; + +import static org.assertj.core.api.Assertions.assertThat; + +import org.junit.Test; + +public class StringPalindromeUnitTest { + + public boolean isPalindrome(String text) { + int forward = 0; + int backward = text.length() - 1; + while (backward > forward) { + char forwardChar = text.charAt(forward++); + char backwardChar = text.charAt(backward--); + if (forwardChar != backwardChar) + return false; + } + return true; + } + + @Test + public void givenIsPalindromeMethod_whenCheckingString_thenFindIfPalindrome() { + assertThat(isPalindrome("madam")).isTrue(); + assertThat(isPalindrome("radar")).isTrue(); + assertThat(isPalindrome("level")).isTrue(); + + assertThat(isPalindrome("baeldung")).isFalse(); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringReverseUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringReverseUnitTest.java new file mode 100644 index 0000000000..bb9b45dc97 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringReverseUnitTest.java @@ -0,0 +1,13 @@ +package com.baeldung.string.interview; + +import static org.junit.Assert.assertEquals; + +import org.junit.Test; + +public class StringReverseUnitTest { + @Test + public void whenUsingInbuildMethods_thenStringReversed() { + String reversed = new StringBuilder("baeldung").reverse().toString(); + assertEquals("gnudleab", reversed); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringSplitUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringSplitUnitTest.java new file mode 100644 index 0000000000..e1cea62462 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringSplitUnitTest.java @@ -0,0 +1,32 @@ +package com.baeldung.string.interview; + +import org.apache.commons.lang3.StringUtils; +import org.junit.Test; +import static org.junit.Assert.assertArrayEquals; + +public class StringSplitUnitTest { + @Test + public void givenCoreJava_whenSplittingStrings_thenSplitted() { + String expected[] = { + "john", + "peter", + "mary" + }; + + String[] splitted = "john,peter,mary".split(","); + assertArrayEquals( expected, splitted ); + } + + @Test + public void givenApacheCommons_whenSplittingStrings_thenSplitted() { + String expected[] = { + "john", + "peter", + "mary" + }; + String[] splitted = StringUtils.split("john peter mary"); + assertArrayEquals( expected, splitted ); + } + + +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringToByteArrayUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringToByteArrayUnitTest.java new file mode 100644 index 0000000000..aee4eedcd6 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringToByteArrayUnitTest.java @@ -0,0 +1,24 @@ +package com.baeldung.string.interview; + +import static org.junit.Assert.assertArrayEquals; + +import java.io.UnsupportedEncodingException; +import java.nio.charset.StandardCharsets; + +import org.junit.Test; + +public class StringToByteArrayUnitTest { + @Test + public void whenGetBytes_thenCorrect() throws UnsupportedEncodingException { + byte[] byteArray1 = "abcd".getBytes(); + byte[] byteArray2 = "efgh".getBytes(StandardCharsets.US_ASCII); + byte[] byteArray3 = "ijkl".getBytes("UTF-8"); + byte[] expected1 = new byte[] { 97, 98, 99, 100 }; + byte[] expected2 = new byte[] { 101, 102, 103, 104 }; + byte[] expected3 = new byte[] { 105, 106, 107, 108 }; + + assertArrayEquals(expected1, byteArray1); + assertArrayEquals(expected2, byteArray2); + assertArrayEquals(expected3, byteArray3); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringToCharArrayUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringToCharArrayUnitTest.java new file mode 100644 index 0000000000..1322d0fa82 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringToCharArrayUnitTest.java @@ -0,0 +1,17 @@ +package com.baeldung.string.interview; + +import static org.junit.Assert.assertEquals; + +import java.util.Arrays; + +import org.junit.Test; + +public class StringToCharArrayUnitTest { + @Test + public void whenConvertingStringToCharArray_thenConversionSuccessful() { + String beforeConvStr = "hello"; + char[] afterConvCharArr = { 'h', 'e', 'l', 'l', 'o' }; + + assertEquals(Arrays.equals(beforeConvStr.toCharArray(), afterConvCharArr), true); + } +} diff --git a/java-strings/src/test/java/com/baeldung/string/interview/StringToIntegerUnitTest.java b/java-strings/src/test/java/com/baeldung/string/interview/StringToIntegerUnitTest.java new file mode 100644 index 0000000000..a905438a84 --- /dev/null +++ b/java-strings/src/test/java/com/baeldung/string/interview/StringToIntegerUnitTest.java @@ -0,0 +1,15 @@ +package com.baeldung.string.interview; + +import org.junit.Test; +import static org.assertj.core.api.Assertions.assertThat; + +public class StringToIntegerUnitTest { + @Test + public void givenString_whenParsingInt_shouldConvertToInt() { + String givenString = "42"; + + int result = Integer.parseInt(givenString); + + assertThat(result).isEqualTo(42); + } +}