diff --git a/dom/base/test/mochitest.ini b/dom/base/test/mochitest.ini
index de3d21163c45..79c906afc00a 100644
--- a/dom/base/test/mochitest.ini
+++ b/dom/base/test/mochitest.ini
@@ -815,6 +815,8 @@ skip-if = buildapp == 'b2g' || toolkit == 'android' # TC: Bug 1144079 - Re-enabl
 skip-if = buildapp == 'b2g' || toolkit == 'android' # TC: Bug 1144079 - Re-enable Mulet mochitests and reftests taskcluster-specific disables.
 [test_websocket2.html]
 skip-if = buildapp == 'b2g' || toolkit == 'android' # TC: Bug 1144079 - Re-enable Mulet mochitests and reftests taskcluster-specific disables.
+[test_websocket3.html]
+skip-if = buildapp == 'b2g' || toolkit == 'android' # TC: Bug 1144079 - Re-enable Mulet mochitests and reftests taskcluster-specific disables.
 [test_websocket_basic.html]
 skip-if = buildapp == 'b2g' || toolkit == 'android'
 [test_websocket_hello.html]
diff --git a/dom/base/test/test_websocket.html b/dom/base/test/test_websocket.html
index dbd054305f59..1b48153234fb 100644
--- a/dom/base/test/test_websocket.html
+++ b/dom/base/test/test_websocket.html
@@ -71,7 +71,7 @@
  * 47. Make sure onerror/onclose aren't called during close()
  */
 
-var first_test = 21;
+var first_test = 31;
 var last_test = 47;
 
 
diff --git a/dom/base/test/test_websocket3.html b/dom/base/test/test_websocket3.html
new file mode 100644
index 000000000000..c7b639c7b096
--- /dev/null
+++ b/dom/base/test/test_websocket3.html
@@ -0,0 +1,225 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta http-equiv="Content-Type" content="text/html;charset=UTF-8"></meta>
+  <title>WebSocket test</title>
+  <script type="text/javascript" src="/tests/SimpleTest/SimpleTest.js"></script>
+  <script type="text/javascript" src="websocket_helpers.js"></script>
+  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />
+</head>
+<body onload="testWebSocket()">
+<script class="testbody" type="text/javascript">
+
+function test21() {
+  return new Promise(function(resolve, reject) {
+    var test21func = function() {
+      var local_ws = new WebSocket("ws://mochi.test:8888/tests/dom/base/test/file_websocket", "test-21");
+      var received_message = false;
+
+      local_ws.onopen = function(e) {
+        e.target.send("client data");
+        forcegc();
+        e.target.onopen = null;
+        forcegc();
+      }
+
+      local_ws.onerror = function() {
+        ok(false, "onerror called on test " + current_test + "!");
+      }
+
+      local_ws.onmessage = function(e) {
+        is(e.data, "server data", "Bad message in test-21");
+        received_message = true;
+        forcegc();
+        e.target.onmessage = null;
+        forcegc();
+      }
+
+      local_ws.onclose = function(e) {
+        shouldCloseCleanly(e);
+        ok(received_message, "close transitioned through onmessage");
+        resolve();
+      }
+
+      local_ws = null;
+      window._test21 = null;
+      forcegc();
+    }
+
+    window._test21 = test21func;
+    window._test21();
+  });
+}
+
+function test22() {
+  return new Promise(function(resolve, reject) {
+    const pref_open = "network.websocket.timeout.open";
+    SpecialPowers.setIntPref(pref_open, 5);
+  
+    var ws = CreateTestWS("ws://sub2.test2.example.org/tests/dom/base/test/file_websocket", "test-22");
+
+    ws.onopen = shouldNotOpen;
+    ws.onerror = ignoreError;
+
+    ws.onclose = function(e) {
+      shouldCloseNotCleanly(e);
+      resolve();
+    }
+  
+    SpecialPowers.clearUserPref(pref_open);
+  });
+}
+
+function test23() {
+  return new Promise(function(resolve, reject) {
+    ok("WebSocket" in window, "WebSocket should be available on window object");
+    resolve();
+  });
+}
+
+function test24() {
+  return new Promise(function(resolve, reject) {
+    var ws = CreateTestWS("ws://mochi.test:8888/tests/dom/base/test/file_websocket", "test-does-not-exist");
+
+    ws.onopen = shouldNotOpen;
+    ws.onclose = function(e) {
+      shouldCloseNotCleanly(e);
+      resolve();
+    }
+
+    ws.onerror = function() {
+    }
+  });
+}
+
+function test25() {
+  return new Promise(function(resolve, reject) {
+    var prots=[];
+  
+    var ws = CreateTestWS("ws://mochi.test:8888/tests/dom/base/test/file_websocket", prots);
+  
+    // This test errors because the server requires a sub-protocol, but
+    // the test just wants to ensure that the ctor doesn't generate an
+    // exception
+    ws.onerror = ignoreError;
+    ws.onopen = shouldNotOpen;
+  
+    ws.onclose = function(e) {
+      is(ws.protocol, "", "test25 subprotocol selection");
+      ok(true, "test 25 protocol array close");
+      resolve();
+    }
+  });
+}
+
+function test26() {
+  return new Promise(function(resolve, reject) {
+    var prots=[""];
+  
+    try {
+      var ws = CreateTestWS("ws://mochi.test:8888/tests/dom/base/test/file_websocket", prots);
+      ok(false, "testing empty element sub protocol array");
+    } catch (e) {
+      ok(true, "testing empty sub element protocol array");
+    }
+
+    resolve();
+  });
+}
+
+function test27() {
+  return new Promise(function(resolve, reject) {
+    var prots=["test27", ""];
+  
+    try {
+      var ws = CreateTestWS("ws://mochi.test:8888/tests/dom/base/test/file_websocket", prots);
+      ok(false, "testing empty element mixed sub protocol array");
+    } catch (e) {
+      ok(true, "testing empty element mixed sub protocol array");
+    }
+
+    resolve();
+  });
+}
+
+function test28() {
+  return new Promise(function(resolve, reject) {
+    var prots=["test28"];
+  
+    var ws = CreateTestWS("ws://mochi.test:8888/tests/dom/base/test/file_websocket", prots);
+
+    ws.onopen = function(e) {
+      ok(true, "test 28 protocol array open");
+      ws.close();
+    }
+  
+    ws.onclose = function(e) {
+      is(ws.protocol, "test28", "test28 subprotocol selection");
+      ok(true, "test 28 protocol array close");
+      resolve();
+    }
+  });
+}
+
+function test29() {
+  return new Promise(function(resolve, reject) {
+    var prots=["test29a", "test29b"];
+  
+    var ws = CreateTestWS("ws://mochi.test:8888/tests/dom/base/test/file_websocket", prots);
+
+    ws.onopen = function(e) {
+      ok(true, "test 29 protocol array open");
+      ws.close();
+    }
+  
+    ws.onclose = function(e) {
+      ok(true, "test 29 protocol array close");
+      resolve();
+    }
+  });
+}
+
+function test30() {
+  return new Promise(function(resolve, reject) {
+    var prots=["test-does-not-exist"];
+    var ws = CreateTestWS("ws://mochi.test:8888/tests/dom/base/test/file_websocket", prots);
+  
+    ws.onopen = shouldNotOpen;
+
+    ws.onclose = function(e) {
+      shouldCloseNotCleanly(e);
+      resolve();
+    }
+
+    ws.onerror = function() {
+    }
+  });
+}
+
+var tests = [
+ test21, // see bug 572975 - same as test 17, but delete strong event listeners
+         // when receiving the message event;
+ test22, // server takes too long to establish the ws connection;
+ test23, // should detect WebSocket on window object;
+ test24, // server rejects sub-protocol string
+ test25, // ctor with valid empty sub-protocol array
+ test26, // ctor with invalid sub-protocol array containing 1 empty element
+ test27, // ctor with invalid sub-protocol array containing an empty element in
+         // list
+ test28, // ctor using valid 1 element sub-protocol array
+ test29, // ctor using all valid 5 element sub-protocol array
+ test30, // ctor using valid 1 element sub-protocol array with element server
+         // will reject
+];
+
+function testWebSocket() {
+  doTest();
+}
+
+</script>
+
+<div id="feedback">
+</div>
+
+</body>
+</html>
