allow the wiring of falsy values (+ test)

backbone.geppetto.js

@@ -145,7 +145,7 @@
             if (this._mappings.hasOwnProperty(key)) {
                 var config = this._mappings[key];
                 if (!overrideRules && config.type === TYPES.SINGLETON) {
-                    if (!config.object) {
+                    if (!config.object && config.clazz) {
                         config.object = this._createAndSetupInstance(config);
                     }
                     output = config.object;

specs/src/geppetto-specs.js

@@ -452,6 +452,7 @@ define([
 
         });
 
+
         describe("when triggering commands", function() {
             var context;
             var CommandClass;

specs/src/resolver-specs.js

@@ -151,9 +151,13 @@ define([
         describe("when mapping a value", function() {
             var key = 'a value';
             var value = {};
+            var spy;
+
+
             beforeEach(function() {
                 context.wireValue(key, value);
             });
+
             it('should be determinable', function() {
                 expect(context.hasWiring(key)).to.be.true;
             });
@@ -165,6 +169,43 @@ define([
                 var second = context.getObject(key);
                 expect(second).to.equal(first);
             });
+
+            it("it should accept the value 'false' as mapped value", function(){
+                spy = sinon.spy(function() {
+                    context.wireValue('false', false);
+                    context.getObject('false');
+                });
+                spy();
+                expect(spy).to.have.not.thrown();
+            });
+
+            it("it should accept empty string as mapped value", function(){
+                spy = sinon.spy(function() {
+                    context.wireValue('empty_string', '');
+                    context.getObject('empty_string');
+                });
+                spy();
+                expect(spy).to.have.not.thrown();
+            });
+
+            it("it should accept 0 as mapped value", function(){
+                spy = sinon.spy(function() {
+                    context.wireValue('zero', 0);
+                    context.getObject('zero');
+                });
+                spy();
+                expect(spy).to.have.not.thrown();
+            });
+
+            it("it should accept null as mapped value", function(){
+                spy = sinon.spy(function() {
+                    context.wireValue('null_value', null);
+                    context.getObject('null_value');
+                });
+                spy();
+                expect(spy).to.have.not.thrown();
+            });
+
         });
         describe("when mapping a class", function() {
             var key = 'a class';