MANTA-4341 Optimize conditional object operations (#382)

Author: chudley

lib/buckets.js

@@ -1233,7 +1233,7 @@ function headBucketObject(bucketName, objectName, opts, cb) {
             }
 
             req.once('result', function onRes(resErr, res) {
-                if (!res) {
+                if (resErr) {
                     readBucketApiErr(resErr, res, cb);
                     return;
                 }

test/integration/buckets-client-basic.test.js

@@ -149,6 +149,16 @@ test('buckets client basic', testOpts, function (suite) {
         });
     });
 
+    test('headBucketObject (not found)', function (t) {
+        clientMethodsToTest.delete('headBucketObject');
+        client.headBucketObject(BUCKET_NAME, OBJECT_NAME + '-not-found',
+                                function (err) {
+            t.ok(err);
+            t.ok(err.statusCode, 404);
+            t.end();
+        });
+    });
+
     test('getBucketObject', function (t) {
         clientMethodsToTest.delete('getBucketObject');
         client.getBucketObject(BUCKET_NAME, OBJECT_NAME,