Implement testResults queue. Retry /status on 404.

The /status API now returns test results that have
been collected but not previously recorded.

Retry /status on 404 because a browser using XHR
may need some more time to reconnect before we
request status again. This is especially true in
our tests, where we request batches rapidly.

lib/app.js

@@ -50,10 +50,16 @@ function fromConfiguration (config) {
         d.method = "GET";
         d.path = "/status/" + id;
         (function moreResults () {
-            http.request(d).on("response", function (res, result) {
+            http.request(d).on("response", function X (res, result) {
                 if (res.statusCode === 200) {
                     ui.results(result);
                     moreResults();
+                } else if (!d._404 && res.statusCode === 404) {
+                    // perhaps the client hasn't connected yet?
+                    d._404 = true;
+                    return setTimeout(function () {
+                        http.request(d).on("response", X);
+                    }, 500);
                 } else {
                     ui.exit("The server says: " + result);
                 }

lib/server.js

@@ -89,8 +89,19 @@ function serveExpress (port, path, cb) {
     });
 
     app.get("/status/:id", function (req, res, params) {
-        if (params.id in testIds) {
-            tests.on(params.id, function (results) {
+        var id = params.id;
+        if (id in testIds) {
+            if (id in testResults) {
+                var results = testResults[id].shift();
+                if (results) {
+                    return res.send(results);
+                } else {
+                    // nothing in the queue
+                    delete testResults[id];
+                    // fallthrough to the test listener
+                }
+            }
+            tests.on(id, function (results) {
                 res.send(results);
             });
         } else {

test/server.js

@@ -34,11 +34,24 @@ function request (code, path, body, method) {
         ).on("response", function X (res, results) {
             var err = null;
             if (res.statusCode !== code)
-                err = res.statusCode + " " + require("http").STATUS_CODES[res.statusCode];
+                err = options.method + " " + options.path
+                      + ": " + res.statusCode
+                      + " " + require("http").STATUS_CODES[res.statusCode];
             if (res.statusCode === 302) { // handle redirects
                 options.path = res.headers.location;
                 return http.request(options).on("response", X);
             }
+            if (res.statusCode === 404 && !options._404) {
+                // when Yeti gives a 404, the resource may be available
+                // in the future. wait a moment then try again.
+                // this typically happens when requesting /status
+                // and a browser, using XHR transport, hasn't
+                // reconnected before the test demands its status
+                options._404 = true;
+                return setTimeout(function () {
+                    http.request(options).on("response", X);
+                }, 500);
+            }
             vow.callback(err, results);
         });
     }