Add default value of 1 to decrement to match increment

lib/dao.js

@@ -391,6 +391,10 @@ module.exports = (function() {
       });
     }
 
+    if (count === undefined) {
+      count = 1;
+    }
+
     return this.increment(fields, 0 - count);
   }
 

test/dao.test.js

@@ -290,6 +290,18 @@ describe(Support.getTestDialectTeaser("DAO"), function () {
       })
     })
 
+    it('with single field and no value', function(done) {
+      var self = this
+      this.User.find(1).complete(function(err, user1) {
+        user1.increment('aNumber').complete(function() {
+          self.User.find(1).complete(function(err, user2) {
+            expect(user2.aNumber).to.be.equal(1)
+            done()
+          })
+        })
+      })
+    })
+
     it('should still work right with other concurrent updates', function(done) {
       var self = this
       this.User.find(1).complete(function (err, user1) {
@@ -388,6 +400,18 @@ describe(Support.getTestDialectTeaser("DAO"), function () {
       })
     })
 
+    it('with single field and no value', function(done) {
+      var self = this
+      this.User.find(1).complete(function(err, user1) {
+        user1.decrement('aNumber').complete(function() {
+          self.User.find(1).complete(function(err, user2) {
+            expect(user2.aNumber).to.be.equal(-1)
+            done()
+          })
+        })
+      })
+    })
+
     it('should still work right with other concurrent updates', function(done) {
       var self = this
       this.User.find(1).complete(function(err, user1) {