Add a default c'tor to MnemonicCode and simplify the unit tests.

core/src/main/java/com/google/bitcoin/crypto/MnemonicCode.java

@@ -16,11 +16,15 @@
 
 package com.google.bitcoin.crypto;
 
+import com.google.bitcoin.core.Sha256Hash;
+import org.spongycastle.crypto.engines.RijndaelEngine;
+import org.spongycastle.crypto.params.KeyParameter;
+import org.spongycastle.util.encoders.Hex;
+
 import java.io.BufferedReader;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
-import java.nio.ByteBuffer;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.ArrayList;
@@ -28,12 +32,6 @@ import java.util.Arrays;
 import java.util.Collections;
 import java.util.List;
 
-import org.spongycastle.crypto.engines.RijndaelEngine;
-import org.spongycastle.crypto.params.KeyParameter;
-import org.spongycastle.util.encoders.Hex;
-
-import com.google.bitcoin.core.Sha256Hash;
-
 /**
  * A MnemonicCode object may be used to convert between binary seed values and
  * lists of words per <a href="https://en.bitcoin.it/wiki/BIP_0039">the BIP 39
@@ -45,19 +43,19 @@ import com.google.bitcoin.core.Sha256Hash;
  */
 
 public class MnemonicCode {
+    private ArrayList<String> wordList;
 
-    private ArrayList<String>	wordList;
+    public static String BIP39_ENGLISH_SHA256 = "ad90bf3beb7b0eb7e5acd74727dc0da96e0a280a258354e7293fb7e211ac03db";
 
-    public static String BIP0039_ENGLISH_SHA256 =
+    public MnemonicCode() throws IOException {
-        "ad90bf3beb7b0eb7e5acd74727dc0da96e0a280a258354e7293fb7e211ac03db";
+        this(MnemonicCode.class.getResourceAsStream("mnemonic/wordlist/english.txt"), BIP39_ENGLISH_SHA256);
+    }
 
     /**
-     * Creates an MnemonicCode object, initializing with words read
+     * Creates an MnemonicCode object, initializing with words read from the supplied input stream.  If a wordListDigest
-     * from the supplied input stream.  If a wordListDigest is
+     * is supplied the digest of the words will be checked.
-     * supplied the digest of the words will be checked.
      */
-    public MnemonicCode(InputStream wordstream, String wordListDigest)
+    public MnemonicCode(InputStream wordstream, String wordListDigest) throws IOException, IllegalArgumentException {
-        throws IOException, IllegalArgumentException {
         BufferedReader br = new BufferedReader(new InputStreamReader(wordstream, "UTF-8"));
         String word;
         this.wordList = new ArrayList<String>();

core/src/test/java/com/google/bitcoin/crypto/MnemonicCodeTest.java

@@ -16,19 +16,19 @@
 
 package com.google.bitcoin.crypto;
 
+import com.google.common.base.Joiner;
+import org.junit.Before;
 import org.junit.Test;
+import org.spongycastle.util.encoders.Hex;
 
-import java.io.InputStream;
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
-import org.spongycastle.util.encoders.Hex;
-
 import static org.junit.Assert.assertEquals;
 
 public class MnemonicCodeTest {
-
     // These vectors are from https://raw.github.com/trezor/python-mnemonic/master/vectors.json
     String vectors[] = {
     
@@ -104,71 +104,39 @@ public class MnemonicCodeTest {
         "c87c135433c16f1ecbf9919dc53dd9f30f85824dc7264d4e1bd644826c902be2", 
         "upper will wisdom term once bean blur inquiry used bamboo frequent hamster amazing cake attack any author mimic leopard day token joy install company",
     };
+    private MnemonicCode mc;
+
+    @Before
+    public void setup() throws IOException {
+        mc = new MnemonicCode();
+    }
 
     @Test
     public void testEncodeVectors() throws Exception {
-        InputStream wordstream = getClass().getResourceAsStream("mnemonic/wordlist/english.txt");
-        MnemonicCode mc = new MnemonicCode(wordstream, MnemonicCode.BIP0039_ENGLISH_SHA256);
-
         for (int ii = 0; ii < vectors.length; ii += 2) {
             List<String> words = mc.encode(Hex.decode(vectors[ii]));
-            assertEquals(vectors[ii+1], join(words));
+            assertEquals(vectors[ii + 1], Joiner.on(' ').join(words));
         }
     }
 
     @Test
     public void testDecodeVectors() throws Exception {
-        InputStream wordstream = getClass().getResourceAsStream("mnemonic/wordlist/english.txt");
-        MnemonicCode mc = new MnemonicCode(wordstream, MnemonicCode.BIP0039_ENGLISH_SHA256);
-
         for (int ii = 0; ii < vectors.length; ii += 2) {
             byte[] seed = mc.decode(split(vectors[ii+1]));
             assertEquals(vectors[ii], new String(Hex.encode(seed)));
         }
     }
 
-    @Test
+    @Test(expected = IllegalArgumentException.class)
     public void testBadSeedLength() throws Exception {
-        InputStream wordstream = getClass().getResourceAsStream("mnemonic/wordlist/english.txt");
+        byte[] seed = Hex.decode("7f7f7f7f7f7f7f7f7f7f7f7f7f7f");
-        MnemonicCode mc = new MnemonicCode(wordstream, MnemonicCode.BIP0039_ENGLISH_SHA256);
+        mc.encode(seed);
-
-        boolean sawException = false;
-        try {
-            byte[] seed = Hex.decode("7f7f7f7f7f7f7f7f7f7f7f7f7f7f");
-            List<String> words = mc.encode(seed);
-        } catch (IllegalArgumentException ex) {
-            sawException = true;
-        }
-        assertEquals(true, sawException);
     }    
 
-    @Test
+    @Test(expected = IllegalArgumentException.class)
     public void testBadWordsLength() throws Exception {
-        InputStream wordstream = getClass().getResourceAsStream("mnemonic/wordlist/english.txt");
+        List<String> words = split("risk tiger venture dinner age assume float denial penalty");
-        MnemonicCode mc = new MnemonicCode(wordstream, MnemonicCode.BIP0039_ENGLISH_SHA256);
+        mc.decode(words);
-
-        boolean sawException = false;
-        try {
-            List<String> words = split("risk tiger venture dinner age assume float denial penalty");
-            byte[] seed = mc.decode(words);
-        } catch (IllegalArgumentException ex) {
-            sawException = true;
-        }
-        assertEquals(true, sawException);
-    }    
-
-    static public String join(List<String> list) {
-        StringBuilder sb = new StringBuilder();
-        boolean first = true;
-        for (String item : list)
-        {
-            if (first)
-                first = false;
-            else
-                sb.append(" ");
-            sb.append(item);
-        }
-        return sb.toString();
     }
 
     static public List<String> split(String words) {