Rewrite as promise_test to suppress testharness error

Differential Revision: https://phabricator.services.mozilla.com/D35449

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1556907
gecko-commit: 99157e588004cdf0a9a5e3183b9c86351ea5459b
gecko-integration-branch: central
gecko-reviewers: annevk
diff --git a/content-security-policy/inside-worker/support/connect-src-self.sub.js b/content-security-policy/inside-worker/support/connect-src-self.sub.js
index 8c533ab..327ffb7 100644
--- a/content-security-policy/inside-worker/support/connect-src-self.sub.js
+++ b/content-security-policy/inside-worker/support/connect-src-self.sub.js
@@ -2,40 +2,42 @@
 importScripts("{{location[server]}}/content-security-policy/support/testharness-helper.js");
 
 // Same-origin
-async_test(t => {
+promise_test(t => {
   var url = "{{location[server]}}/common/text-plain.txt?same-origin-fetch";
   assert_no_csp_event_for_url(t, url);
 
-  fetch(url)
-    .then(t.step_func_done(r => assert_equals(r.status, 200)));
+  return fetch(url)
+    .then(t.step_func(r => assert_equals(r.status, 200)));
 }, "Same-origin 'fetch()' in " + self.location.protocol + self.location.search);
 
-async_test(t => {
+promise_test(t => {
   var url = "{{location[server]}}/common/text-plain.txt?same-origin-xhr";
   assert_no_csp_event_for_url(t, url);
 
-  var xhr = new XMLHttpRequest();
-  xhr.open("GET", url);
-  xhr.onload = t.step_func_done();
-  xhr.onerror = t.unreached_func();
-  xhr.send();
+  return new Promise((resolve, reject) => {
+    var xhr = new XMLHttpRequest();
+    xhr.open("GET", url);
+    xhr.onload = t.step_func(resolve);
+    xhr.onerror = t.step_func(_ => reject("xhr.open should success."));
+    xhr.send();
+  });
 }, "Same-origin XHR in " + self.location.protocol + self.location.search);
 
 // Cross-origin
-async_test(t => {
+promise_test(t => {
   var url = "http://{{domains[www]}}:{{ports[http][1]}}/common/text-plain.txt?cross-origin-fetch";
 
-  Promise.all([
+  return Promise.all([
     // TODO(mkwst): A 'securitypolicyviolation' event should fire.
     fetch(url)
       .catch(t.step_func(e => assert_true(e instanceof TypeError)))
-  ]).then(t.step_func_done());
+  ]);
 }, "Cross-origin 'fetch()' in " + self.location.protocol + self.location.search);
 
-async_test(t => {
+promise_test(t => {
   var url = "http://{{domains[www]}}:{{ports[http][1]}}/common/text-plain.txt?cross-origin-xhr";
 
-  Promise.all([
+  return Promise.all([
     // TODO(mkwst): A 'securitypolicyviolation' event should fire.
     new Promise((resolve, reject) => {
       var xhr = new XMLHttpRequest();
@@ -44,16 +46,15 @@
       xhr.onerror = t.step_func(resolve);
       xhr.send();
     })
-  ]).then(t.step_func_done());
+  ]);
 }, "Cross-origin XHR in " + self.location.protocol + self.location.search);
 
 // Same-origin redirecting to cross-origin
-async_test(t => {
+promise_test(t => {
   var url = "{{location[server]}}/common/redirect-opt-in.py?status=307&location=http://{{domains[www]}}:{{ports[http][1]}}/common/text-plain.txt?cross-origin-fetch";
 
   // TODO(mkwst): A 'securitypolicyviolation' event should fire.
-  fetch(url)
-    .catch(t.step_func_done(e => assert_true(e instanceof TypeError)))
+  return promise_rejects(t, new TypeError, fetch(url));
 }, "Same-origin => cross-origin 'fetch()' in " + self.location.protocol + self.location.search);
 
 done();