Fixes #160 - Added error message when w-bind is used, but no correspo…

…nding JS module

taglib/TransformHelper/handleWidgetBind.js

@@ -39,6 +39,10 @@ module.exports = function handleWidgetBind() {
 
     if (bindAttrValue == null) {
         modulePath = this.getDefaultWidgetModule();
+        if (!modulePath) {
+            this.addError('Invalid "w-bind" attribute. No corresponding JavaScript module found in the same directory (either "widget.js" or "index.js"). Actual: ' + modulePath);
+            return;
+        }
     } else if (bindAttr.isLiteralValue()) {
         modulePath = bindAttr.literalValue; // The value of the literal value
         if (typeof modulePath !== 'string') {

test/autotests-server/w-bind-missing-widget/index.foo

@@ -0,0 +1,7 @@
+module.exports = require('marko-widgets').defineComponent({
+    template: require('./template.marko'),
+
+    init: function() {
+
+    }
+});

test/autotests-server/w-bind-missing-widget/template.marko

@@ -0,0 +1 @@
+div w-bind

test/autotests-server/w-bind-missing-widget/test.js

@@ -0,0 +1,7 @@
+var expect = require('chai').expect;
+
+module.exports = function(helpers) {
+    expect(function() {
+        require('./template.marko');
+    }).to.throw(/Invalid "w-bind" attribute/);
+};