Provide stubbed visitor implementation

Part of #889

spec/visitor.js

@@ -0,0 +1,48 @@
+/*global Handlebars */
+
+describe('Visitor', function() {
+  if (!Handlebars.Visitor) {
+    return;
+  }
+
+  function ast_for(template) {
+    var ast = Handlebars.parse(template);
+    return Handlebars.print(ast);
+  }
+
+  it('should provide coverage', function() {
+    // Simply run the thing and make sure it does not fail and that all of the
+    // stub methods are executed
+    var visitor = new Handlebars.Visitor();
+    visitor.accept(Handlebars.parse('{{#foo (bar 1 "1" true) foo=@data}}{{!comment}}{{> bar }} {{/foo}}'));
+  });
+
+  it('should traverse to stubs', function() {
+    var visitor = new Handlebars.Visitor();
+
+    visitor.PARTIAL_NAME = function(partialName) {
+      equal(partialName.name, 'bar');
+    };
+
+    visitor.STRING = function(string) {
+      equal(string.string, '2');
+    };
+    visitor.NUMBER = function(number) {
+      equal(number.stringModeValue, 1);
+    };
+    visitor.BOOLEAN = function(bool) {
+      equal(bool.stringModeValue, true);
+    };
+    visitor.ID = function(id) {
+      equal(id.original, 'foo.bar');
+    };
+    visitor.content = function(content) {
+      equal(content.string, ' ');
+    };
+    visitor.comment = function(comment) {
+      equal(comment.comment, 'comment');
+    };
+
+    visitor.accept(Handlebars.parse('{{#foo.bar (foo.bar 1 "2" true) foo=@foo.bar}}{{!comment}}{{> bar }} {{/foo.bar}}'));
+  });
+});