Bug 1453260 - run test script in specific page only r=aswan

Use a more specific entry point for the test than
"http://mochitest.test:8888" to make sure that the test is only started
once, when the test opens a tab with the entry point.

MozReview-Commit-ID: 7iAFREDuACu

--HG--
extra : rebase_source : 6ab46b1114dc824f29d0bf21ffa784cd14651447

browser/components/extensions/test/browser/browser_ext_connect_and_move_tabs.js

@@ -11,7 +11,7 @@ function loadExtension() {
     manifest: {
       "content_scripts": [{
         "js": ["script.js"],
-        "matches": ["http://mochi.test/"],
+        "matches": ["http://mochi.test/?discoTest"],
       }],
     },
     background() {
@@ -21,7 +21,7 @@ function loadExtension() {
           browser.test.sendMessage("port_disconnected");
         });
         port.onMessage.addListener(async msg => {
-          browser.test.assertEq("connect_from_contentscript", msg, "expected message");
+          browser.test.assertEq("connect_from_script", msg, "expected message");
           // Move a tab to a new window and back. Regression test for bugzil.la/1448674
           let {windowId, id: tabId, index} = port.sender.tab;
           await browser.windows.create({tabId});
@@ -65,7 +65,7 @@ function loadExtension() {
           });
           browser.runtime.sendMessage("disconnect-me");
         });
-        port.postMessage("connect_from_contentscript");
+        port.postMessage("connect_from_script");
       },
     },
   });
@@ -74,7 +74,7 @@ function loadExtension() {
 add_task(async function contentscript_connect_and_move_tabs() {
   let extension = loadExtension();
   await extension.startup();
-  await BrowserTestUtils.openNewForegroundTab(gBrowser, "http://mochi.test:8888/");
+  await BrowserTestUtils.openNewForegroundTab(gBrowser, "http://mochi.test:8888/?discoTest");
   await extension.awaitMessage("port_ping_ponged_before_disconnect");
   await extension.awaitMessage("port_disconnected");
   // Must use gBrowser.selectedTab instead of the return value of