[api test] Added winston.Container.has and associated tests

lib/winston/container.js

@@ -58,6 +58,16 @@ Container.prototype.get = Container.prototype.add = function (id, options) {
   return this.loggers[id];
 };
 
+//
+// ### function close (id)
+// #### @id {string} **Optional** Id of the Logger instance to find
+// Returns a boolean value indicating if this instance
+// has a logger with the specified `id`.
+//
+Container.prototype.has = function (id) {
+  return !!this.loggers[id];
+};
+
 //
 // ### function close (id)
 // #### @id {string} **Optional** Id of the Logger instance to close

test/container-test.js

@@ -32,6 +32,17 @@ vows.describe('winston/container').addBatch({
           assert.isTrue(existing === logger);
         }
       },
+      "the has() method": {
+        topic: function (logger, container) {
+          this.callback.apply(this, arguments);
+        },
+        "should indicate `default-test` logger exists": function (existing, container) {
+          assert.isTrue(container.has('default-test'));
+        },
+        "should indicate `not-has` logger doesnt exists": function (existing, container) {
+          assert.isFalse(container.has('not-has'));
+        }
+      },
       "the close() method": {
         topic: function (logger, container) {
           this.callback.apply(this, arguments);