Added base64 unit test

src/test/java/com/rarchives/ripme/tst/Base64Test.java

@@ -1,4 +1,11 @@
 package com.rarchives.ripme.tst;
 
-public class Base64Test {
+import junit.framework.TestCase;
+import com.rarchives.ripme.utils.Base64;
+
+public class Base64Test extends TestCase {
+
+    public void testDecode() {
+        assertEquals("test", new String(Base64.decode("dGVzdA==")));
+    }
 }