Issue 2148 - Rewrite the testpages test suite

pages/filters/websocket.tmpl

 title = $websocket
 template = testcase
 
 {% set testcase_moreinfo = [
   ("Filter Options", "https://adblockplus.org/filters#options"),
 ] %}
 
 
 <script>
-function pagelog(message) {
-  var log = document.getElementById("testcase-fo-websocket");
-  log.innerText = log.innerText + message + "\n";
-  console.log(message);
-}
-
 function ws_open(evt) {
   pagelog("Connected");
   websocket.send("Test message was echoed back");
 }
 function ws_close(evt) {
   pagelog("Disconnected");
 }
 function ws_message(evt) {
   pagelog("Received message: ");
   pagelog(evt.data);
@@ skipping 21 matching lines @@
 
 <section class="site-panel">
   <h2>$websocket</h2>
   <p>Check that usage of the $websocket filter option works as expected.</p>
   <p>With the filter displayed below each test case added to ABP (or with the testcase subscription installed and active), the websocket connection should be blocked and not echo back the test message.</p>
 </section>
 
 <section class="site-panel">
   <h2>Test case</h2>
   <div class="testcase-container">
-   <div class="testcase-row"><h3>WebSocket Request</h3><div id="testcase-fo-websocket"></div></div>
+   <div class="testcase-row"><h3>WebSocket Request</h3><div id="testcase-output"></div></div>
   </div>
   <h3>Filters</h3>
   <pre>$websocket,domain=testpages.adblockplus.org</pre>
 </section>