Base64CodecTest.java

/*
 * Copyright 2010-2017 Amazon.com, Inc. or its affiliates. All Rights
 * Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License").
 * You may not use this file except in compliance with the License.
 * A copy of the License is located at
 *
 *  http://aws.amazon.com/apache2.0
 *
 * or in the "license" file accompanying this file. This file is
 * distributed
 * on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either
 * express or implied. See the License for the specific language
 * governing
 * permissions and limitations under the License.
 */
package com.amazonaws.util;

import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.UUID;

import org.junit.Assert;
import org.junit.Test;

public class Base64CodecTest 
{
    @Test
    public void testVectorsPerRfc4648() throws NoSuchAlgorithmException, UnsupportedEncodingException {
        String[] testVectors = {
                "",
                "f",
                "fo",
                "foo",
                "foob",
                "fooba",
                "foobar",
        };
        String[] expected = {
                "",
                "Zg==",
                "Zm8=",
                "Zm9v",
                "Zm9vYg==",
                "Zm9vYmE=",
                "Zm9vYmFy",
        };
        
        for (int i=0; i < testVectors.length; i++) {
            String data = testVectors[i];
            byte[] source = data.getBytes("UTF-8");
            String b64encoded = Base64.encodeAsString(data.getBytes("UTF-8"));
            Assert.assertEquals(expected[i], b64encoded);
            byte[] b64 = b64encoded.getBytes("UTF-8");
            
            byte[] decoded = Base64.decode(b64);
            Assert.assertTrue(Arrays.equals(source, decoded));
        }
    }
    
    @Test
    public void testCodecConsistency() throws NoSuchAlgorithmException, UnsupportedEncodingException {
        byte[] decoded = null;         
        
        for (int h=0; h < 1000; h++) {
            byte[] digest = MessageDigest.getInstance("SHA-1").digest(UUID.randomUUID().toString().getBytes("UTF-8"));
            String b64Encoded = Base64.encodeAsString(digest);
            decoded = Base64.decode(b64Encoded);
            Assert.assertTrue(Arrays.equals(decoded, digest));
        }
    }
    
    @Test
    public void testImpossibleCases() {
        final String[] BASE64_IMPOSSIBLE_CASES = {
            "ZE==",
            "ZmC=",
            "Zm9vYE==",
            "Zm9vYmC=",
        };
    
        for (String s: BASE64_IMPOSSIBLE_CASES) {
            try {
                Base64.decode(s);
                Assert.fail();
            } catch(IllegalArgumentException ex) {
                // expected
            }
        }
    }
}