tests: fix child-process-fork-dgram on SmartOS.

Send messages until both the parent and the child process have received
at least one message. If at least one of them doesn't receive any
message, the test runner will make the test timeout.

Fixes #8046.

test/simple/test-child-process-fork-dgram.js

@@ -19,6 +19,20 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
+/*
+ * The purpose of this test is to make sure that when forking a process,
+ * sending a fd representing a UDP socket to the child and sending messages
+ * to this endpoint, these messages are distributed to the parent and the
+ * child process.
+ *
+ * Because it's not really possible to predict how the messages will be
+ * distributed among the parent and the child processes, we keep sending
+ * messages until both the parent and the child received at least one
+ * message. The worst case scenario is when either one never receives
+ * a message. In this case the test runner will timeout after 60 secs
+ * and the test will fail.
+ */
+
 var dgram = require('dgram');
 var fork = require('child_process').fork;
 var assert = require('assert');
@@ -38,12 +52,11 @@ if (process.argv[2] === 'child') {
       server = clusterServer;
 
       server.on('message', function () {
-        childCollected += 1;
+        process.send('gotMessage');
       });
 
     } else if (msg === 'stop') {
       server.close();
-      process.send(childCollected);
       process.removeListener('message', removeMe);
     }
   });
@@ -52,48 +65,49 @@ if (process.argv[2] === 'child') {
   var server = dgram.createSocket('udp4');
   var client = dgram.createSocket('udp4');
   var child = fork(__filename, ['child']);
+
   var msg = new Buffer('Some bytes');
 
-  var parentCollected = 0;
-  var childCollected = 0;
+  var childGotMessage = false;
+  var parentGotMessage = false;
+
   server.on('message', function (msg, rinfo) {
-    parentCollected += 1;
+    parentGotMessage = true;
   });
 
   server.on('listening', function () {
     child.send('server', server);
 
+    child.once('message', function (msg) {
+      if (msg === 'gotMessage') {
+        childGotMessage = true;
+      }
+    });
+
     sendMessages();
   });
 
   var sendMessages = function () {
-    var wait = 0;
-    var send = 0;
-    var total = 100;
-
     var timer = setInterval(function () {
-      send += 1;
-      if (send === total) {
-        clearInterval(timer);
-      }
-
       client.send(msg, 0, msg.length, common.PORT, '127.0.0.1', function(err) {
           if (err) throw err;
-
-          wait += 1;
-          if (wait === total) {
-            shutdown();
-          }
         }
       );
+
+      /*
+       * Both the parent and the child got at least one message,
+       * test passed, clean up everyting.
+       */
+      if (parentGotMessage && childGotMessage) {
+        clearInterval(timer);
+        shutdown();
+      }
+
     }, 1);
   };
 
   var shutdown = function () {
     child.send('stop');
-    child.once('message', function (collected) {
-      childCollected = collected;
-    });
 
     server.close();
     client.close();
@@ -102,7 +116,7 @@ if (process.argv[2] === 'child') {
   server.bind(common.PORT, '127.0.0.1');
 
   process.once('exit', function () {
-    assert(childCollected > 0);
-    assert(parentCollected > 0);
+    assert(parentGotMessage);
+    assert(childGotMessage);
   });
 }