diff --git a/lib/templates/test-body-footer.html b/lib/templates/test-body-footer.html
index 0bf9e109..f847f1ed 100644
--- a/lib/templates/test-body-footer.html
+++ b/lib/templates/test-body-footer.html
@@ -1,4 +1,6 @@
 <script>
+  // Make synchronous requests in phantom to avoid killing the runner before the coverage completes.
+  var REQUEST_ASYNC = !/PhantomJS/.test(window.navigator.userAgent);
   function sendCoverage(callback) {
    Object.keys(require.entries).forEach(function(file) {
       // Only load non-test files from the project
@@ -16,7 +18,7 @@
     var data = JSON.stringify(coverageData || {});
 
     var request = new XMLHttpRequest();
-    request.open('POST', '/write-coverage', true);
+    request.open('POST', '/write-coverage', REQUEST_ASYNC);
     request.setRequestHeader('Content-Type', 'application/json; charset=utf-8');
     request.send(data);
     request.responseType = 'json';