[fix] coerce HMAC#update input as String

Author: kares

src/main/java/org/jruby/ext/openssl/HMAC.java

@@ -168,7 +168,7 @@ public IRubyObject initialize_copy(final IRubyObject obj) {
 
     @JRubyMethod(name = { "update", "<<" })
     public IRubyObject update(final IRubyObject obj) {
-        data.append(obj.asString().getByteList());
+        data.append(obj.convertToString().getByteList());
         return this;
     }
 
@@ -188,10 +188,6 @@ public IRubyObject hexdigest() {
         return getRuntime().newString( toHEX(getSignatureBytes()) );
     }
 
-    String getAlgorithm() {
-        return mac.getAlgorithm();
-    }
-
     private byte[] getSignatureBytes() {
         mac.reset();
         mac.update(data.getUnsafeBytes(), data.getBegin(), data.getRealSize());

src/test/ruby/test_hmac.rb

@@ -41,4 +41,20 @@ def test_hexdigest_with_empty_key
     assert_equal "4acb10ca3965a14a080297db0921950c", result
   end
 
+  def test_update_string_coercion
+    h1 = OpenSSL::HMAC.new("KEY", "SHA256")
+    h2 = OpenSSL::HMAC.new("KEY", "SHA256")
+
+    str_like = Object.new
+    def str_like.to_str
+      "DATA"
+    end
+
+    h1.update(str_like)
+    h2.update("DATA")
+    assert_equal h2.digest, h1.digest
+
+    assert_raise(TypeError) { h1.update(1) }
+  end
+
 end