Fix ls command to return links, and improve test

Author: ianopolous

src/main/java/io/ipfs/api/IPFS.java

@@ -101,8 +101,13 @@ public List<MerkleNode> add(List<NamedStreamable> files, boolean wrap, boolean h
     }
 
     public List<MerkleNode> ls(Multihash hash) throws IOException {
-        Map res = retrieveMap("ls?arg=" + hash);
-        return ((List<Object>) res.get("Objects")).stream().map(x -> MerkleNode.fromJSON((Map) x)).collect(Collectors.toList());
+        Map reply = retrieveMap("ls?arg=" + hash);
+        return ((List<Object>) reply.get("Objects"))
+                .stream()
+                .flatMap(x -> ((List<Object>)((Map) x).get("Links"))
+                        .stream()
+                        .map(MerkleNode::fromJSON))
+                .collect(Collectors.toList());
     }
 
     public byte[] cat(Multihash hash) throws IOException {

src/main/java/io/ipfs/api/MerkleNode.java

@@ -103,4 +103,9 @@ public Object toJSON() {
     public String toJSONString() {
         return JSONParser.toString(toJSON());
     }
+
+    @Override
+    public String toString() {
+        return hash + "-" + name.orElse("");
+    }
 }

src/test/java/io/ipfs/api/APITest.java

@@ -102,8 +102,9 @@ public void wrappedSingleFileTest() throws IOException {
 
     @Test
     public void dirTest() throws IOException {
-        NamedStreamable.DirWrapper dir = new NamedStreamable.DirWrapper("root", Arrays.asList());
-        MerkleNode addResult = ipfs.add(dir).get(0);
+        NamedStreamable dir = new NamedStreamable.FileWrapper(new File("java"));
+        List<MerkleNode> add = ipfs.add(dir);
+        MerkleNode addResult = add.get(add.size() - 1);
         List<MerkleNode> ls = ipfs.ls(addResult.hash);
         Assert.assertTrue(ls.size() > 0);
     }