Decrypt test

build.gradle

@@ -44,9 +44,12 @@ repositories {
 dependencies {
 	compile "com.google.code.gson:gson:2.2.2"
 	compile "org.java-websocket:Java-WebSocket:1.4.0"
+
 	testCompile "org.mockito:mockito-all:1.8.5"
 	testCompile "org.powermock:powermock-module-junit4:1.4.11"
 	testCompile "org.powermock:powermock-api-mockito:1.4.11"
+
+	testImplementation "com.google.truth:truth:1.0.1"
 }
 
 
@@ -66,6 +69,7 @@ javadoc {
 	exclude "**/com/pusher/client/channel/impl/*"
 	exclude "**/com/pusher/client/connection/impl/*"
 	exclude "**/com/pusher/client/connection/websocket/*"
+	exclude "**/com/pusher/client/crypto/nacl/*"
 	exclude "**/org/java_websocket/*"
 	exclude "**/com/pusher/client/example/*"
 	options.linkSource = true

src/main/java/com/pusher/client/util/Base64.java

@@ -0,0 +1,39 @@
+package com.pusher.client.util;
+
+// copied from: https://stackoverflow.com/a/4265472/501940
+public class Base64 {
+
+    private final static char[] ALPHABET =
+            "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/".toCharArray();
+
+    private static int[] toInt = new int[128];
+
+    static {
+        for (int i = 0; i < ALPHABET.length; i++) {
+            toInt[ALPHABET[i]] = i;
+        }
+    }
+
+    public static byte[] decode(String base64String) {
+        int delta = base64String.endsWith("==") ? 2 : base64String.endsWith("=") ? 1 : 0;
+        byte[] buffer = new byte[base64String.length() * 3 / 4 - delta];
+        int mask = 0xFF;
+        int index = 0;
+        for (int i = 0; i < base64String.length(); i += 4) {
+            int c0 = toInt[base64String.charAt(i)];
+            int c1 = toInt[base64String.charAt(i + 1)];
+            buffer[index++] = (byte) (((c0 << 2) | (c1 >> 4)) & mask);
+            if (index >= buffer.length) {
+                return buffer;
+            }
+            int c2 = toInt[base64String.charAt(i + 2)];
+            buffer[index++] = (byte) (((c1 << 4) | (c2 >> 2)) & mask);
+            if (index >= buffer.length) {
+                return buffer;
+            }
+            int c3 = toInt[base64String.charAt(i + 3)];
+            buffer[index++] = (byte) (((c2 << 6) | c3) & mask);
+        }
+        return buffer;
+    }
+}

src/test/java/com/pusher/client/crypto/nacl/SecretBoxOpenerTest.java

@@ -0,0 +1,28 @@
+package com.pusher.client.crypto.nacl;
+
+import static com.google.common.truth.Truth.assertThat;
+
+import com.pusher.client.util.Base64;
+import org.junit.Before;
+import org.junit.Test;
+
+public class SecretBoxOpenerTest {
+
+    byte[] key = Base64.decode("6071zp2l/GPnDPDXNWTJDHyIZ8pZMvQrYsa4xuTKK2c=");
+    SecretBoxOpener subject;
+
+    @Before
+    public void setUp() {
+        subject = new SecretBoxOpener(key);
+    }
+
+    @Test
+    public void open() {
+        byte[] cipher = Base64.decode("tvttPE2PRQp0bWDmaPyiEU8YJGztmTvTN77OoPwftTNTdDgJXwxHQPE=");
+        byte[] nonce = Base64.decode("xsbOS0KylAV2ziTDHrP/7rSFqpCOah3p");
+
+        byte[] clearText = subject.open(cipher, nonce);
+
+        assertThat(new String(clearText)).isEqualTo("{\"message\":\"hello world\"}");
+    }
+}