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To add Implementation of Base64 Algorithm (#6586)
* feat: base64 algorithm implementation * feat: test coverage implementation of Base64Test.java * Update DIRECTORY.md * fix: build and lint fix update * patch: linter fix * fix: enforce strict RFC 4648 compliance in Base64 decoding * fix: enforce strict rfc 4648 compliance in base64 decoding --------- Co-authored-by: Oleksandr Klymenko <alexanderklmn@gmail.com>
This commit is contained in:
Nithin U
183
src/test/java/com/thealgorithms/conversions/Base64Test.java
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183
src/test/java/com/thealgorithms/conversions/Base64Test.java
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package com.thealgorithms.conversions;
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import static org.junit.jupiter.api.Assertions.assertArrayEquals;
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import static org.junit.jupiter.api.Assertions.assertEquals;
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import static org.junit.jupiter.api.Assertions.assertThrows;
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import org.junit.jupiter.api.Test;
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import org.junit.jupiter.params.ParameterizedTest;
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import org.junit.jupiter.params.provider.CsvSource;
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/**
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* Test cases for Base64 encoding and decoding.
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*
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* Author: Nithin U.
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* Github: https://github.com/NithinU2802
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*/
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class Base64Test {
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@Test
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void testBase64Alphabet() {
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// Test that all Base64 characters are handled correctly
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String allChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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String encoded = Base64.encode(allChars);
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String decoded = Base64.decodeToString(encoded);
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assertEquals(allChars, decoded);
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}
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@ParameterizedTest
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@CsvSource({"'', ''", "A, QQ==", "AB, QUI=", "ABC, QUJD", "ABCD, QUJDRA==", "Hello, SGVsbG8=", "'Hello World', SGVsbG8gV29ybGQ=", "'Hello, World!', 'SGVsbG8sIFdvcmxkIQ=='", "'The quick brown fox jumps over the lazy dog', 'VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wcyBvdmVyIHRoZSBsYXp5IGRvZw=='",
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"123456789, MTIzNDU2Nzg5", "'Base64 encoding test', 'QmFzZTY0IGVuY29kaW5nIHRlc3Q='"})
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void
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testStringEncoding(String input, String expected) {
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assertEquals(expected, Base64.encode(input));
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}
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@ParameterizedTest
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@CsvSource({"'', ''", "QQ==, A", "QUI=, AB", "QUJD, ABC", "QUJDRA==, ABCD", "SGVsbG8=, Hello", "'SGVsbG8gV29ybGQ=', 'Hello World'", "'SGVsbG8sIFdvcmxkIQ==', 'Hello, World!'", "'VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wcyBvdmVyIHRoZSBsYXp5IGRvZw==', 'The quick brown fox jumps over the lazy dog'",
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"MTIzNDU2Nzg5, 123456789", "'QmFzZTY0IGVuY29kaW5nIHRlc3Q=', 'Base64 encoding test'"})
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void
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testStringDecoding(String input, String expected) {
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assertEquals(expected, Base64.decodeToString(input));
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}
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@Test
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void testByteArrayEncoding() {
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byte[] input = {72, 101, 108, 108, 111};
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String expected = "SGVsbG8=";
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assertEquals(expected, Base64.encode(input));
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}
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@Test
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void testByteArrayDecoding() {
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String input = "SGVsbG8=";
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byte[] expected = {72, 101, 108, 108, 111};
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assertArrayEquals(expected, Base64.decode(input));
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}
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@Test
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void testRoundTripEncoding() {
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String[] testStrings = {"", "A", "AB", "ABC", "Hello, World!", "The quick brown fox jumps over the lazy dog", "1234567890", "Special chars: !@#$%^&*()_+-=[]{}|;:,.<>?",
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"Unicode: வணக்கம்", // Tamil for "Hello"
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"Multi-line\nstring\rwith\tdifferent\nwhitespace"};
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for (String original : testStrings) {
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String encoded = Base64.encode(original);
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String decoded = Base64.decodeToString(encoded);
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assertEquals(original, decoded, "Round trip failed for: " + original);
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}
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}
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@Test
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void testRoundTripByteArrayEncoding() {
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byte[][] testArrays = {{}, {0}, {-1}, {0, 1, 2, 3, 4, 5}, {-128, -1, 0, 1, 127}, {72, 101, 108, 108, 111, 44, 32, 87, 111, 114, 108, 100, 33}};
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for (byte[] original : testArrays) {
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String encoded = Base64.encode(original);
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byte[] decoded = Base64.decode(encoded);
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assertArrayEquals(original, decoded, "Round trip failed for byte array");
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}
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}
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@Test
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void testBinaryData() {
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// Test with binary data that might contain null bytes
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byte[] binaryData = new byte[256];
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for (int i = 0; i < 256; i++) {
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binaryData[i] = (byte) i;
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}
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String encoded = Base64.encode(binaryData);
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byte[] decoded = Base64.decode(encoded);
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assertArrayEquals(binaryData, decoded);
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}
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@Test
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void testNullInputEncoding() {
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assertThrows(IllegalArgumentException.class, () -> Base64.encode((String) null));
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assertThrows(IllegalArgumentException.class, () -> Base64.encode((byte[]) null));
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}
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@Test
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void testNullInputDecoding() {
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assertThrows(IllegalArgumentException.class, () -> Base64.decode(null));
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assertThrows(IllegalArgumentException.class, () -> Base64.decodeToString(null));
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}
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@Test
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void testInvalidBase64Characters() {
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assertThrows(IllegalArgumentException.class, () -> Base64.decode("SGVsbG8@"));
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assertThrows(IllegalArgumentException.class, () -> Base64.decode("SGVsbG8#"));
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assertThrows(IllegalArgumentException.class, () -> Base64.decode("SGVsbG8$"));
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assertThrows(IllegalArgumentException.class, () -> Base64.decode("SGVsbG8%"));
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}
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@Test
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void testInvalidLength() {
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// Length must be multiple of 4
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assertThrows(IllegalArgumentException.class, () -> Base64.decode("Q"));
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assertThrows(IllegalArgumentException.class, () -> Base64.decode("QQ"));
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assertThrows(IllegalArgumentException.class, () -> Base64.decode("QQQ"));
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}
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@Test
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void testInvalidPaddingPosition() {
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// '=' can only appear at the end
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assertThrows(IllegalArgumentException.class, () -> Base64.decode("Q=QQ"));
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assertThrows(IllegalArgumentException.class, () -> Base64.decode("Q=Q="));
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assertThrows(IllegalArgumentException.class, () -> Base64.decode("=QQQ"));
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}
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@Test
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void testPaddingVariations() {
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// Test different padding scenarios '='
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assertEquals("A", Base64.decodeToString("QQ=="));
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assertEquals("AB", Base64.decodeToString("QUI="));
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assertEquals("ABC", Base64.decodeToString("QUJD"));
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}
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@Test
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void testPaddingConsistency() {
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// Ensure that strings requiring different amounts of padding encode/decode correctly
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String[] testCases = {"A", "AB", "ABC", "ABCD", "ABCDE", "ABCDEF"};
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for (String test : testCases) {
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String encoded = Base64.encode(test);
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String decoded = Base64.decodeToString(encoded);
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assertEquals(test, decoded);
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// Verify padding is correct
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int expectedPadding = (3 - (test.length() % 3)) % 3;
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int actualPadding = 0;
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for (int i = encoded.length() - 1; i >= 0 && encoded.charAt(i) == '='; i--) {
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actualPadding++;
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}
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assertEquals(expectedPadding, actualPadding, "Incorrect padding for: " + test);
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}
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}
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@Test
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void testLargeData() {
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// Test with larger data to ensure scalability
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StringBuilder largeString = new StringBuilder();
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for (int i = 0; i < 1000; i++) {
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largeString.append("This is a test string for Base64 encoding. ");
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}
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String original = largeString.toString();
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String encoded = Base64.encode(original);
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String decoded = Base64.decodeToString(encoded);
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assertEquals(original, decoded);
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}
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@Test
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void testEmptyAndSingleCharacter() {
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// Test edge cases
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assertEquals("", Base64.encode(""));
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assertEquals("", Base64.decodeToString(""));
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assertEquals("QQ==", Base64.encode("A"));
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assertEquals("A", Base64.decodeToString("QQ=="));
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}
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}
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