Fix RealmTest MD5 String computation, close AsyncHttpClient#1301

Author: slandelle

client/src/test/java/org/asynchttpclient/RealmTest.java

@@ -16,11 +16,11 @@
 import static org.asynchttpclient.Dsl.*;
 import static org.testng.Assert.assertEquals;
 
-import java.math.BigInteger;
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 
 import org.asynchttpclient.uri.Uri;
+import org.asynchttpclient.util.StringUtils;
 import org.testng.annotations.Test;
 
 public class RealmTest {
@@ -42,18 +42,16 @@ public void testClone() {
     }
 
     @Test(groups = "standalone")
-    public void testOldDigestEmptyString() {
-        String qop = "";
-        testOldDigest(qop);
+    public void testOldDigestEmptyString() throws Exception {
+        testOldDigest("");
     }
 
     @Test(groups = "standalone")
-    public void testOldDigestNull() {
-        String qop = null;
-        testOldDigest(qop);
+    public void testOldDigestNull() throws Exception {
+        testOldDigest(null);
     }
 
-    private void testOldDigest(String qop) {
+    private void testOldDigest(String qop) throws Exception {
         String user = "user";
         String pass = "pass";
         String realm = "realm";
@@ -65,7 +63,8 @@ private void testOldDigest(String qop) {
                 .setUri(uri)//
                 .setMethodName(method)//
                 .setRealmName(realm)//
-                .setQop(qop).build();
+                .setQop(qop)//
+                .build();
 
         String ha1 = getMd5(user + ":" + realm + ":" + pass);
         String ha2 = getMd5(method + ":" + uri.getPath());
@@ -75,7 +74,7 @@ private void testOldDigest(String qop) {
     }
 
     @Test(groups = "standalone")
-    public void testStrongDigest() {
+    public void testStrongDigest() throws Exception {
         String user = "user";
         String pass = "pass";
         String realm = "realm";
@@ -88,7 +87,8 @@ public void testStrongDigest() {
                 .setUri(uri)//
                 .setMethodName(method)//
                 .setRealmName(realm)//
-                .setQop(qop).build();
+                .setQop(qop)//
+                .build();
 
         String nc = orig.getNc();
         String cnonce = orig.getCnonce();
@@ -99,19 +99,10 @@ public void testStrongDigest() {
         assertEquals(orig.getResponse(), expectedResponse);
     }
 
-    private String getMd5(String what) {
-        try {
-            MessageDigest md = MessageDigest.getInstance("MD5");
-            md.update(what.getBytes(StandardCharsets.ISO_8859_1));
-            byte[] hash = md.digest();
-            BigInteger bi = new BigInteger(1, hash);
-            String result = bi.toString(16);
-            if (result.length() % 2 != 0) {
-                return "0" + result;
-            }
-            return result;
-        } catch (Exception e) {
-            throw new RuntimeException(e);
-        }
+    private String getMd5(String what) throws Exception {
+        MessageDigest md = MessageDigest.getInstance("MD5");
+        md.update(what.getBytes(StandardCharsets.ISO_8859_1));
+        byte[] hash = md.digest();
+        return StringUtils.toHexString(hash);
     }
 }