allow nested contexts with no topics

Author: cloudhead

lib/vows.js

@@ -274,20 +274,21 @@ vows.tell = function (subject, tests) {
             // If it encounters a `topic` function, it waits for the returned
             // promise to emit (the topic), at which point it runs the functions under it,
             // passing the topic as an argument.
-            (function run(ctx) {
+            (function run(ctx, lastTopic) {
                 var ctxAdded = false;
 
-                if ('topic' in ctx.tests) {
-
+                topic = lastTopic = ('topic' in ctx.tests) ? ctx.tests.topic
+                                                           : lastTopic;
+                if (topic) {
                     // Topic isn't a function, wrap it into one.
-                    if (typeof(ctx.tests.topic) !== 'function') {
-                        ctx.tests.topic = (function (topic) {
+                    if (typeof(topic) !== 'function') {
+                        topic = (function (topic) {
                             return function () { return topic };
-                        })(ctx.tests.topic);
+                        })(topic);
                     }
 
                     // Run the topic, passing the previous context topics
-                    topic = ctx.tests.topic.apply(ctx.env, ctx.topics);
+                    topic = topic.apply(ctx.env, ctx.topics);
 
                     // If the topic doesn't return an event emitter (such as a promise),
                     // we create it ourselves, and emit the value on the next tick.
@@ -334,11 +335,11 @@ vows.tell = function (subject, tests) {
                         if (topic) {
                             topic.addListener("success", function (vow, ctx) {
                                 return function (val) {
-                                    return run(new(Context)(vow, ctx, env));
+                                    return run(new(Context)(vow, ctx, env), lastTopic);
                                 };
                             }(vow, ctx));
                         } else {
-                            run(new(Context)(vow, ctx, env));
+                            run(new(Context)(vow, ctx, env), lastTopic);
                         }
                     }
                 });

test/vows-test.js

@@ -97,6 +97,16 @@ vows.describe("Vows", {
             }
         }
     },
+    "Nested contexts with no topics": {
+        topic: 45,
+        "should": {
+            "pass": {
+                "the value down": function (topic) {
+                    assert.equal(topic, 45);
+                }
+            }
+        }
+    },
     "Non-promise return value": {
         topic: function () { return 1 },
         "should be converted to a promise": function (val) {