testContext.compile is now promise-aware

  - Async test contexts are promise objects. Keep them as promises
    that resolve with compiled contexts
  - Properly fixes async test cases/specs and runner timing issues

lib/buster-test/test-context.js

@@ -1,16 +1,19 @@
 if (typeof module === "object" && typeof require === "function") {
     var buster = require("buster-core");
+    var when = require("when");
 }
 
 buster.testContext = (function () {
+    var bctx;
+
     function empty(context) {
         return context.tests.length == 0 &&
             context.contexts.length == 0;
     }
 
     function filterContexts(contexts, filter, prefix) {
         return reduce(contexts, [], function (filtered, context) {
-            var ctx = buster.testContext.filter(context, filter, prefix);
+            var ctx = bctx.filter(context, filter, prefix);
             if (ctx.tests.length > 0 || ctx.contexts.length > 0) {
                 filtered.push(ctx);
             }
@@ -44,14 +47,21 @@ buster.testContext = (function () {
         if (!context.tests && typeof context.parse == "function") {
             return context.parse();
         }
-
         return context;
     }
 
     function compile(contexts, filter) {
         return reduce(contexts, [], function (compiled, ctx) {
-            ctx = buster.testContext.filter(parse(ctx), filter);
-            if (!empty(ctx)) compiled.push(ctx);
+            if (when.isPromise(ctx)) {
+                var deferred = when.defer();
+                ctx.then(function (context) {
+                    deferred.resolve(bctx.filter(parse(context), filter));
+                });
+                compiled.push(deferred.promise);
+            } else {
+                ctx = bctx.filter(parse(ctx), filter);
+                if (!empty(ctx)) compiled.push(ctx);
+            }
             return compiled;
         });
     }
@@ -76,7 +86,8 @@ buster.testContext = (function () {
         return acc;
     }
 
-    return { compile: compile, filter: filter };
+    bctx = { compile: compile, filter: filter };
+    return bctx;
 }());
 
 if (typeof module == "object") {

test/unit/buster-test/test-context-test.js

@@ -262,5 +262,18 @@ buster.util.testCase("ContextFilterTest", {
 
         assert.equals(contexts.length, 1);
         assert.equals(contexts[0].tests.length, 2);
+    },
+
+    "should return promise for promise input": function () {
+        var context = buster.testCase("Some tests", {
+            "test 1": function () {},
+            "test 2": function () {},
+            "should be dropped": function () {}
+        });
+        var promise = when(context);
+        var contexts = buster.testContext.compile([promise], "test ");
+
+        assert.equals(contexts.length, 1);
+        assert.isFunction(contexts[0].then);
     }
 });