--- a/browser/components/extensions/test/browser/browser_ext_browserAction_context.js
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_context.js
@@ -54,17 +54,17 @@ function* runTests(options) {
         // run the next test.
         new Promise(resolve => {
           return browser.tabs.query({active: true, currentWindow: true}, resolve);
         }).then(tabs => {
           return checkDetails(expecting, tabs[0].id);
         }).then(() => {
           // Check that the actual icon has the expected values, then
           // run the next test.
-          browser.test.sendMessage("nextTest", expecting, tests.length);
+          browser.test.sendMessage("nextTest", {expecting, remaining: tests.length});
         });
       });
     }
 
     browser.test.onMessage.addListener((msg) => {
       if (msg != "runNextTest") {
         browser.test.fail("Expecting 'runNextTest' message");
       }
@@ -81,19 +81,19 @@ function* runTests(options) {
 
   let extension = ExtensionTestUtils.loadExtension({
     manifest: options.manifest,
 
     files: options.files || {},
 
     background: `(${background})(${options.getTests})`,
   });
-
+  yield extension.startup();
 
-  let browserActionId = makeWidgetId(extension.id) + "-browser-action";
+  let browserActionId = `${makeWidgetId(extension.id)}-browser-action`;
 
   function checkDetails(details) {
     let button = document.getElementById(browserActionId);
 
     ok(button, "button exists");
 
     let title = details.title || options.manifest.name;
 
@@ -113,31 +113,25 @@ function* runTests(options) {
 
       is(badgeColor, expectedColor, "badge color is correct");
     }
 
 
     // TODO: Popup URL.
   }
 
-  let awaitFinish = new Promise(resolve => {
-    extension.onMessage("nextTest", (expecting, testsRemaining) => {
-      checkDetails(expecting);
-
-      if (testsRemaining) {
-        extension.sendMessage("runNextTest");
-      } else {
-        resolve();
-      }
-    });
-  });
-
-  yield extension.startup();
-
-  yield awaitFinish;
+  while (true) {
+    let results = yield extension.awaitMessage("nextTest");
+    checkDetails(results.expecting);
+    if (results.remaining > 0) {
+      extension.sendMessage("runNextTest");
+    } else {
+      break;
+    }
+  }
 
   yield extension.unload();
 }
 
 add_task(function* testTabSwitchContext() {
   yield runTests({
     manifest: {
       "browser_action": {

--- a/browser/components/extensions/test/browser/browser_ext_browserAction_pageAction_icon.js
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_pageAction_icon.js
@@ -249,25 +249,25 @@ add_task(function* testDetailsObjects() 
       "a.png": imageBuffer,
       "data/2.png": imageBuffer,
       "data/100.png": imageBuffer,
       "data/a.png": imageBuffer,
       "data/a-x2.png": imageBuffer,
     },
   });
 
+  yield extension.startup();
+  let tests = yield extension.awaitMessage("ready");
+
   const RESOLUTION_PREF = "layout.css.devPixelsPerPx";
 
-  let pageActionId = makeWidgetId(extension.id) + "-page-action";
+  let pageActionId = `${makeWidgetId(extension.id)}-page-action`;
   let browserActionWidget = getBrowserActionWidget(extension);
 
 
-  yield extension.startup();
-  let tests = yield extension.awaitMessage("ready");
-
   for (let test of tests) {
     extension.sendMessage("setIcon", test);
     yield extension.awaitMessage("iconSet");
 
     let browserActionButton = browserActionWidget.forWindow(window).node;
     let pageActionImage = document.getElementById(pageActionId);
 
 

--- a/browser/components/extensions/test/browser/browser_ext_browserAction_popup.js
+++ b/browser/components/extensions/test/browser/browser_ext_browserAction_popup.js
@@ -115,52 +115,58 @@ function* testInArea(area) {
           if (msg != "next-test") {
             browser.test.fail("Expecting 'next-test' message");
           }
 
           if (tests.length) {
             let test = tests.shift();
             test();
           } else {
+            browser.test.sendMessage("next-test", {finished: true});
             browser.test.notifyPass("browseraction-tests-done");
           }
         });
 
         browser.test.sendMessage("next-test");
       },
     },
   });
 
   extension.onMessage("send-click", () => {
     clickBrowserAction(extension);
   });
 
-  let widget;
-  extension.onMessage("next-test", Task.async(function* (expecting = {}) {
-    if (!widget) {
-      widget = getBrowserActionWidget(extension);
-      CustomizableUI.addWidgetToArea(widget.id, area);
+  yield extension.startup();
+
+  let widget = getBrowserActionWidget(extension);
+  CustomizableUI.addWidgetToArea(widget.id, area);
+
+  while (true) {
+    let expecting = yield extension.awaitMessage("next-test");
+    expecting = expecting || {};
+    if (expecting.finished) {
+      break;
     }
     if (expecting.expectClosed) {
       let panel = getBrowserActionPopup(extension);
       ok(panel, "Expect panel to exist");
       yield promisePopupShown(panel);
 
       extension.sendMessage("close-popup");
 
       yield promisePopupHidden(panel);
       ok(true, "Panel is closed");
     } else {
       yield closeBrowserAction(extension);
     }
 
     extension.sendMessage("next-test");
-  }));
+  }
 
-  yield Promise.all([extension.startup(), extension.awaitFinish("browseraction-tests-done")]);
+  yield extension.awaitFinish("browseraction-tests-done");
 
   yield extension.unload();
 
   let view = document.getElementById(widget.viewId);
   is(view, null, "browserAction view removed from document");
 }
 
 add_task(function* testBrowserActionInToolbar() {

--- a/browser/components/extensions/test/browser/browser_ext_incognito_popup.js
+++ b/browser/components/extensions/test/browser/browser_ext_incognito_popup.js
@@ -44,42 +44,45 @@ add_task(function* testIncognitoPopup() 
           browser.test.sendMessage("click-browserAction");
 
           return awaitPopup(window.id);
         }).then(msg => {
           browser.test.assertEq(window.incognito, msg.incognito, "Correct incognito status in browserAction popup");
         });
       };
 
-      const URL = "http://example.com/incognito";
-      let windowReady = new Promise(resolve => {
-        browser.tabs.onUpdated.addListener(function listener(tabId, changed, tab) {
-          if (changed.status == "complete" && tab.url == URL) {
-            browser.tabs.onUpdated.removeListener(listener);
-            resolve();
-          }
+      browser.test.onMessage.addListener(msg => {
+        const URL = "http://example.com/incognito";
+        let windowReady = new Promise(resolve => {
+          browser.tabs.onUpdated.addListener(function listener(tabId, changed, tab) {
+            if (changed.status == "complete" && tab.url == URL) {
+              browser.tabs.onUpdated.removeListener(listener);
+              resolve();
+            }
+          });
+        });
+
+        browser.windows.getCurrent().then(window => {
+          return testWindow(window);
+        }).then(() => {
+          return browser.windows.create({incognito: true, url: URL});
+        }).then(window => {
+          return windowReady.then(() => {
+            return testWindow(window);
+          }).then(() => {
+            return browser.windows.remove(window.id);
+          });
+        }).then(() => {
+          browser.test.notifyPass("incognito");
+        }).catch(error => {
+          browser.test.fail(`Error: ${error} :: ${error.stack}`);
+          browser.test.notifyFail("incognito");
         });
       });
-
-      browser.windows.getCurrent().then(window => {
-        return testWindow(window);
-      }).then(() => {
-        return browser.windows.create({incognito: true, url: URL});
-      }).then(window => {
-        return windowReady.then(() => {
-          return testWindow(window);
-        }).then(() => {
-          return browser.windows.remove(window.id);
-        });
-      }).then(() => {
-        browser.test.notifyPass("incognito");
-      }).catch(error => {
-        browser.test.fail(`Error: ${error} :: ${error.stack}`);
-        browser.test.notifyFail("incognito");
-      });
+      browser.test.sendMessage("ready");
     },
 
     files: {
       "popup.html": '<html><head><meta charset="utf-8"><script src="popup.js"></script></head></html>',
 
       "popup.js": function() {
         browser.windows.getCurrent().then(win => {
           browser.runtime.sendMessage({
@@ -88,20 +91,24 @@ add_task(function* testIncognitoPopup() 
             incognito: browser.extension.inIncognitoContext,
           });
           window.close();
         });
       },
     },
   });
 
+  yield extension.startup();
+
   extension.onMessage("click-browserAction", () => {
     clickBrowserAction(extension, Services.wm.getMostRecentWindow("navigator:browser"));
   });
 
   extension.onMessage("click-pageAction", () => {
     clickPageAction(extension, Services.wm.getMostRecentWindow("navigator:browser"));
   });
 
-  yield extension.startup();
+  yield extension.awaitMessage("ready");
+  extension.sendMessage("go");
+
   yield extension.awaitFinish("incognito");
   yield extension.unload();
 });

--- a/browser/components/extensions/test/browser/browser_ext_pageAction_context.js
+++ b/browser/components/extensions/test/browser/browser_ext_pageAction_context.js
@@ -29,17 +29,17 @@ function* runTests(options) {
     // and passes control back to the outer test scope.
     function nextTest() {
       let test = tests.shift();
 
       test(expecting => {
         function finish() {
           // Check that the actual icon has the expected values, then
           // run the next test.
-          browser.test.sendMessage("nextTest", expecting, tests.length);
+          browser.test.sendMessage("nextTest", {expecting, remaining: tests.length});
         }
 
         if (expecting) {
           // Check that the API returns the expected values, and then
           // run the next test.
           getDetails().then(details => {
             browser.test.assertEq(expecting.title, details.title,
                                   "expected value from getTitle");
@@ -70,29 +70,29 @@ function* runTests(options) {
       if (msg == "runTests") {
         runTests();
       } else if (msg == "runNextTest") {
         nextTest();
       } else {
         browser.test.fail(`Unexpected message: ${msg}`);
       }
     });
-
-    runTests();
   }
 
   let extension = ExtensionTestUtils.loadExtension({
     manifest: options.manifest,
 
     files: options.files || {},
 
     background: `(${background})(${options.getTests})`,
   });
 
-  let pageActionId = makeWidgetId(extension.id) + "-page-action";
+  yield extension.startup();
+
+  let pageActionId = `${makeWidgetId(extension.id)}-page-action`;
   let currentWindow = window;
   let windows = [];
 
   function checkDetails(details) {
     let image = currentWindow.document.getElementById(pageActionId);
     if (details == null) {
       ok(image == null || image.hidden, "image is hidden");
     } else {
@@ -104,41 +104,38 @@ function* runTests(options) {
       is(image.getAttribute("tooltiptext"), title, "image title is correct");
       is(image.getAttribute("aria-label"), title, "image aria-label is correct");
       // TODO: Popup URL.
     }
   }
 
   let testNewWindows = 1;
 
-  let awaitFinish = new Promise(resolve => {
-    extension.onMessage("nextTest", (expecting, testsRemaining) => {
-      checkDetails(expecting);
+  extension.sendMessage("runTests");
+  while (true) {
+    let result = yield extension.awaitMessage("nextTest");
 
-      if (testsRemaining) {
-        extension.sendMessage("runNextTest");
-      } else if (testNewWindows) {
-        testNewWindows--;
+    checkDetails(result.expecting);
+
+    if (result.remaining > 0) {
+      extension.sendMessage("runNextTest");
+    } else if (testNewWindows) {
+      testNewWindows--;
 
-        BrowserTestUtils.openNewBrowserWindow().then(window => {
-          windows.push(window);
-          currentWindow = window;
-          return focusWindow(window);
-        }).then(() => {
-          extension.sendMessage("runTests");
-        });
-      } else {
-        resolve();
-      }
-    });
-  });
-
-  yield extension.startup();
-
-  yield awaitFinish;
+      BrowserTestUtils.openNewBrowserWindow().then(window => {
+        windows.push(window);
+        currentWindow = window;
+        return focusWindow(window);
+      }).then(() => {
+        extension.sendMessage("runTests");
+      });
+    } else if (testNewWindows == 0) {
+      break;
+    }
+  }
 
   yield extension.unload();
 
   let node = document.getElementById(pageActionId);
   is(node, null, "pageAction image removed from document");
 
   currentWindow = null;
   for (let win of windows.splice(0)) {

--- a/browser/components/extensions/test/browser/browser_ext_pageAction_popup.js
+++ b/browser/components/extensions/test/browser/browser_ext_pageAction_popup.js
@@ -131,24 +131,28 @@ add_task(function* testPageActionPopup()
           browser.pageAction.show(tabId).then(() => {
             browser.test.sendMessage("next-test");
           });
         });
       },
     },
   });
 
-  let pageActionId = makeWidgetId(extension.id) + "-page-action";
-  let panelId = makeWidgetId(extension.id) + "-panel";
+  yield extension.startup();
+
+  let pageActionId = `${makeWidgetId(extension.id)}-page-action`;
+  let panelId = `${makeWidgetId(extension.id)}-panel`;
 
   extension.onMessage("send-click", () => {
     clickPageAction(extension);
   });
 
-  extension.onMessage("next-test", Task.async(function* (expecting = {}) {
+  while (true) {
+    let expecting = yield extension.awaitMessage("next-test");
+    expecting = expecting || {};
     let panel = document.getElementById(panelId);
     if (expecting.expectClosed) {
       ok(panel, "Expect panel to exist");
       yield promisePopupShown(panel);
 
       extension.sendMessage("close-popup");
 
       yield promisePopupHidden(panel);
@@ -159,20 +163,22 @@ add_task(function* testPageActionPopup()
     }
 
     if (panel) {
       panel = document.getElementById(panelId);
       is(panel, null, "panel successfully removed from document after hiding");
     }
 
     extension.sendMessage("next-test");
-  }));
 
+    if (expecting.expectClosed) {
+      break;
+    }
+  }
 
-  yield extension.startup();
   yield extension.awaitFinish("pageaction-tests-done");
 
   yield extension.unload();
 
   let node = document.getElementById(pageActionId);
   is(node, null, "pageAction image removed from document");
 
   let panel = document.getElementById(panelId);