Test command runs after TestRPC starts listening

bin/exec.js

@@ -146,6 +146,7 @@ try {
   cleanUp(msg + err);
 }
 
+new Promise((resolve, reject) => {
   // Run modified testrpc with large block limit, on (hopefully) unused port.
   // (Changes here should be also be added to the before() block of test/run.js).
   if (!config.norpc) {
@@ -156,9 +157,16 @@ if (!config.norpc) {
     testrpcProcess = childprocess.exec(command + testrpcOptions, null, err => {
       if (err) cleanUp('testRpc errored after launching as a childprocess.');
     });
-  log(`Launching testrpc on port ${port}`);
+    testrpcProcess.stdout.on('data', data => {
+      if (data.includes('Listening')) {
+        log(`Launched testrpc on port ${port}`);
+        return resolve();
       }
-
+    });
+  } else {
+    return resolve();
+  }
+}).then(() => {
   // Run truffle (or config.testCommand) over instrumented contracts in the
   // coverage environment folder. Shell cd command needs to be invoked
   // as its own statement for command line options to work, apparently.
@@ -214,3 +222,4 @@ try {
 
   // Finish
   cleanUp();
+});