resolves mochajs#1393: kill children with more effort on SIGINT

bin/mocha

@@ -54,3 +54,10 @@ proc.on('exit', function (code, signal) {
     }
   });
 });
+
+// terminate children.
+process.on('SIGINT', function () {
+  proc.kill('SIGINT'); // calls runner.abort()
+  proc.kill('SIGTERM'); // if that didn't work, we're probably in an infinite loop, so make it die.
+  process.kill(process.pid, 'SIGINT');
+});

test/acceptance/misc/exit.js

@@ -10,4 +10,9 @@ describe('exit', function(){
       console.log('all done');
     }, 2500)
   })
+
+  it('should kill all processes when SIGINT received', function () {
+    // uncomment to test
+    //while (true) {}
+  });
 })