diff --git a/browser/base/content/test/general/browser_bug423833.js b/browser/base/content/test/general/browser_bug423833.js
index 8d95b894c670f..7fe61fca15097 100644
--- a/browser/base/content/test/general/browser_bug423833.js
+++ b/browser/base/content/test/general/browser_bug423833.js
@@ -84,6 +84,7 @@ function test2Setup() {
 }
 
 function testOpenFrameInTab() {
+  /* eslint-disable mozilla/no-cpows-in-tests */
   if (gBrowser.contentDocument.location.href == "about:blank")
     // Wait another cycle
     return;
@@ -92,6 +93,7 @@ function testOpenFrameInTab() {
 
   // We should now have the error page in a new, active tab.
   is(gBrowser.contentDocument.location.href, invalidPage, "New tab should have page url, not about:neterror");
+  /* eslint-enable mozilla/no-cpows-in-tests */
 
   // Clear up the new tab, and punt to test 3
   gBrowser.removeCurrentTab();
diff --git a/browser/base/content/test/general/browser_bug561636.js b/browser/base/content/test/general/browser_bug561636.js
index b680944bb70c0..bee293d2d071b 100644
--- a/browser/base/content/test/general/browser_bug561636.js
+++ b/browser/base/content/test/general/browser_bug561636.js
@@ -285,6 +285,7 @@ add_task(async function() {
     Services.obs.addObserver(gObserver, "invalidformsubmit");
 
     executeSoon(function() {
+      // eslint-disable-next-line mozilla/no-cpows-in-tests
       browser.contentDocument.getElementById("s").click();
     });
   });
@@ -330,6 +331,7 @@ add_task(async function() {
   checkPopupShow();
   await checkChildFocus(browser, gInvalidFormPopup.firstChild.textContent);
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let inputPromise = promiseWaitForEvent(gBrowser.contentDocument.getElementById("i"), "input");
   EventUtils.synthesizeKey("f", {});
   await inputPromise;
diff --git a/browser/base/content/test/general/browser_bug575561.js b/browser/base/content/test/general/browser_bug575561.js
index 9837aa3baded7..f25fa94444b82 100644
--- a/browser/base/content/test/general/browser_bug575561.js
+++ b/browser/base/content/test/general/browser_bug575561.js
@@ -74,6 +74,7 @@ async function testLink(aLinkIndexOrFunction, pinTab, expectNewTab, testSubFrame
   let href;
   if (typeof aLinkIndexOrFunction === "function") {
     ok(!browser.isRemoteBrowser, "don't pass a function for a remote browser");
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let link = aLinkIndexOrFunction(browser.contentDocument);
     info("Clicking " + link.textContent);
     link.click();
diff --git a/browser/base/content/test/general/browser_bug678392.js b/browser/base/content/test/general/browser_bug678392.js
index 3b79b6fa086b1..b73cc71d91275 100644
--- a/browser/base/content/test/general/browser_bug678392.js
+++ b/browser/base/content/test/general/browser_bug678392.js
@@ -36,6 +36,7 @@ function test() {
 
 function load(aTab, aUrl, aCallback) {
   aTab.linkedBrowser.addEventListener("load", function(aEvent) {
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     waitForFocus(aCallback, content);
   }, {capture: true, once: true});
   aTab.linkedBrowser.loadURI(aUrl);
diff --git a/browser/base/content/test/general/browser_bug767836_perwindowpb.js b/browser/base/content/test/general/browser_bug767836_perwindowpb.js
index d8dd5f158dae2..8307277ac2daa 100644
--- a/browser/base/content/test/general/browser_bug767836_perwindowpb.js
+++ b/browser/base/content/test/general/browser_bug767836_perwindowpb.js
@@ -75,6 +75,7 @@ function openNewTab(aWindow, aCallback) {
   aWindow.BrowserOpenTab();
 
   let browser = aWindow.gBrowser.selectedBrowser;
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   if (browser.contentDocument.readyState === "complete") {
     executeSoon(aCallback);
     return;
diff --git a/browser/base/content/test/general/browser_e10s_about_page_triggeringprincipal.js b/browser/base/content/test/general/browser_e10s_about_page_triggeringprincipal.js
index f77e9db12a606..1edb1a05d8f2b 100644
--- a/browser/base/content/test/general/browser_e10s_about_page_triggeringprincipal.js
+++ b/browser/base/content/test/general/browser_e10s_about_page_triggeringprincipal.js
@@ -16,6 +16,7 @@ add_task(async function test_principal_click() {
   await kAboutPagesRegistered;
   await BrowserTestUtils.withNewTab("about:test-about-principal-parent", async function(browser) {
     let loadPromise = BrowserTestUtils.browserLoaded(browser, false, "about:test-about-principal-child");
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let myLink = browser.contentDocument.getElementById("aboutchildprincipal");
     myLink.click();
     await loadPromise;
diff --git a/browser/base/content/test/general/browser_gZipOfflineChild.js b/browser/base/content/test/general/browser_gZipOfflineChild.js
index c271c04956ccd..5dcb1cf45f5ed 100644
--- a/browser/base/content/test/general/browser_gZipOfflineChild.js
+++ b/browser/base/content/test/general/browser_gZipOfflineChild.js
@@ -72,6 +72,7 @@ function test() {
   registerCleanupFunction(() => gBrowser.removeCurrentTab());
 
   BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser).then(() => {
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let window = gBrowser.selectedBrowser.contentWindow;
 
     window.addEventListener("message", handleMessageEvents);
diff --git a/browser/base/content/test/general/browser_keywordSearch_postData.js b/browser/base/content/test/general/browser_keywordSearch_postData.js
index f4e6f532aef16..fdf3ff54dbac8 100644
--- a/browser/base/content/test/general/browser_keywordSearch_postData.js
+++ b/browser/base/content/test/general/browser_keywordSearch_postData.js
@@ -67,6 +67,7 @@ function doTest() {
   info("Running test: " + gCurrTest.name);
 
   waitForLoad(function() {
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let loadedText = gBrowser.contentDocument.body.textContent;
     ok(loadedText, "search page loaded");
     let needle = "searchterms=" + gCurrTest.expectText;
diff --git a/browser/base/content/test/general/browser_tabfocus.js b/browser/base/content/test/general/browser_tabfocus.js
index 281b4409f26c3..137709bb851ef 100644
--- a/browser/base/content/test/general/browser_tabfocus.js
+++ b/browser/base/content/test/general/browser_tabfocus.js
@@ -91,6 +91,7 @@ function focusInChild() {
     content.document.getElementById(message.data.id)[message.data.type]();
   });
 
+  /* eslint-disable mozilla/no-cpows-in-tests */
   addMessageListener("Browser:GetFocusedElement", function getFocusedElement(message) {
     var focusedWindow = {};
     var node = contentFM.getFocusedElementForWindow(content, false, focusedWindow);
@@ -128,6 +129,7 @@ function focusElementInChild(elementid, type) {
     browser.contentDocument.getElementById(elementid)[type]();
   }
 }
+/* eslint-enable mozilla/no-cpows-in-tests */
 
 add_task(async function() {
   tab1 = BrowserTestUtils.addTab(gBrowser);
diff --git a/browser/base/content/test/newtab/browser_newtab_focus.js b/browser/base/content/test/newtab/browser_newtab_focus.js
index 15f64c88175bd..ffc4999fa92f9 100644
--- a/browser/base/content/test/newtab/browser_newtab_focus.js
+++ b/browser/base/content/test/newtab/browser_newtab_focus.js
@@ -67,7 +67,7 @@ function promiseNoMuteNotificationOnFirstSession() {
  * Wait for the onboarding tour notification opens
  */
 function promiseTourNotificationOpened(browser) {
-  function isOpened() {
+  return ContentTask.spawn(browser, {}, function() {
     let doc = content && content.document;
     let notification = doc.querySelector("#onboarding-notification-bar");
     if (notification && notification.classList.contains("onboarding-opened")) {
@@ -88,6 +88,5 @@ function promiseTourNotificationOpened(browser) {
       });
       observer.observe(doc.body, { childList: true });
     });
-  }
-  return ContentTask.spawn(browser, {}, isOpened);
+  });
 }
diff --git a/browser/base/content/test/pageinfo/browser_pageinfo_image_info.js b/browser/base/content/test/pageinfo/browser_pageinfo_image_info.js
index 372f3fc0b60a1..d9ad8f68e920e 100644
--- a/browser/base/content/test/pageinfo/browser_pageinfo_image_info.js
+++ b/browser/base/content/test/pageinfo/browser_pageinfo_image_info.js
@@ -14,6 +14,7 @@ function test() {
   gBrowser.selectedTab = BrowserTestUtils.addTab(gBrowser);
 
   gBrowser.selectedBrowser.addEventListener("load", function() {
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     var doc = gBrowser.contentDocument;
     var testImg = doc.getElementById("test-image");
     var pageInfo = BrowserPageInfo(gBrowser.selectedBrowser.currentURI.spec,
diff --git a/browser/base/content/test/popupNotifications/browser_popupNotification_keyboard.js b/browser/base/content/test/popupNotifications/browser_popupNotification_keyboard.js
index 4ca220ac15f46..ee18baa9283a8 100644
--- a/browser/base/content/test/popupNotifications/browser_popupNotification_keyboard.js
+++ b/browser/base/content/test/popupNotifications/browser_popupNotification_keyboard.js
@@ -192,6 +192,7 @@ var tests = [
         if (gMultiProcessBrowser) {
           is(Services.focus.focusedElement, browser);
         } else {
+          // eslint-disable-next-line mozilla/no-cpows-in-tests
           is(Services.focus.focusedElement, browser.contentDocument.getElementById("test-input"));
         }
 
diff --git a/browser/base/content/test/sidebar/browser_bug409481.js b/browser/base/content/test/sidebar/browser_bug409481.js
index 7c93b494427fd..8b3655c9403a2 100644
--- a/browser/base/content/test/sidebar/browser_bug409481.js
+++ b/browser/base/content/test/sidebar/browser_bug409481.js
@@ -37,9 +37,11 @@ function runTest(event) {
   sidebar.contentDocument.removeEventListener("load", delayedRunTest, true);
 
   var browser = sidebar.contentDocument.getElementById("web-panels-browser");
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   var div = browser && browser.contentDocument.getElementById("test_bug409481");
   ok(div && div.textContent == "Content!", "Sidebar content loaded");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   var link = browser && browser.contentDocument.getElementById("link");
   sidebar.contentDocument.addEventListener("popupshown", contextMenuOpened);
 
@@ -60,6 +62,7 @@ function copyLinkCommandExecuted(event) {
 
   var sidebar = document.getElementById("sidebar");
   var browser = sidebar.contentDocument.getElementById("web-panels-browser");
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   var textbox = browser && browser.contentDocument.getElementById("textbox");
   textbox.focus();
   document.commandDispatcher.getControllerForCommand("cmd_paste").doCommand("cmd_paste");
diff --git a/browser/base/content/test/tabcrashed/browser_autoSubmitRequest.js b/browser/base/content/test/tabcrashed/browser_autoSubmitRequest.js
index daf974b06965d..a3fcebbe30d07 100644
--- a/browser/base/content/test/tabcrashed/browser_autoSubmitRequest.js
+++ b/browser/base/content/test/tabcrashed/browser_autoSubmitRequest.js
@@ -32,6 +32,7 @@ add_task(async function test_show_form() {
     // Now crash the browser.
     await BrowserTestUtils.crashBrowser(browser);
 
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let doc = browser.contentDocument;
 
     // Ensure the request is visible. We can safely reach into
@@ -76,6 +77,7 @@ add_task(async function test_show_form() {
     // Now crash the browser.
     await BrowserTestUtils.crashBrowser(browser);
 
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let doc = browser.contentDocument;
 
     // Ensure the request is NOT visible. We can safely reach into
diff --git a/browser/base/content/test/tabcrashed/browser_clearEmail.js b/browser/base/content/test/tabcrashed/browser_clearEmail.js
index 0b753bffa8c88..c621ab514cd19 100644
--- a/browser/base/content/test/tabcrashed/browser_clearEmail.js
+++ b/browser/base/content/test/tabcrashed/browser_clearEmail.js
@@ -37,6 +37,7 @@ add_task(async function test_clear_email() {
     await BrowserTestUtils.crashBrowser(browser,
                                         /* shouldShowTabCrashPage */ true,
                                         /* shouldClearMinidumps */ false);
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let doc = browser.contentDocument;
 
     // Since about:tabcrashed will run in the parent process, we can safely
@@ -48,6 +49,7 @@ add_task(async function test_clear_email() {
       Email: "",
     });
 
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let restoreTab = browser.contentDocument.getElementById("restoreTab");
     restoreTab.click();
     await BrowserTestUtils.waitForEvent(tab, "SSTabRestored");
@@ -63,4 +65,3 @@ add_task(async function test_clear_email() {
     prefs.setCharPref("email", originalEmail);
   });
 });
-
diff --git a/browser/base/content/test/tabcrashed/browser_showForm.js b/browser/base/content/test/tabcrashed/browser_showForm.js
index f7e6d26d5183e..b451c09c534a2 100644
--- a/browser/base/content/test/tabcrashed/browser_showForm.js
+++ b/browser/base/content/test/tabcrashed/browser_showForm.js
@@ -26,6 +26,7 @@ add_task(async function test_show_form() {
     // Now crash the browser.
     await BrowserTestUtils.crashBrowser(browser);
 
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let doc = browser.contentDocument;
 
     // Ensure the checkbox is checked. We can safely reach into
diff --git a/browser/base/content/test/tabcrashed/browser_shown.js b/browser/base/content/test/tabcrashed/browser_shown.js
index 57c3ba4218d15..330227e7fd3d6 100644
--- a/browser/base/content/test/tabcrashed/browser_shown.js
+++ b/browser/base/content/test/tabcrashed/browser_shown.js
@@ -56,6 +56,7 @@ function crashTabTestHelper(fieldValues, expectedExtra) {
 
     let tab = gBrowser.getTabForBrowser(browser);
     await BrowserTestUtils.crashBrowser(browser);
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let doc = browser.contentDocument;
 
     // Since about:tabcrashed will run in the parent process, we can safely
@@ -82,6 +83,7 @@ function crashTabTestHelper(fieldValues, expectedExtra) {
     }
 
     let crashReport = promiseCrashReport(expectedExtra);
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let restoreTab = browser.contentDocument.getElementById("restoreTab");
     restoreTab.click();
     await BrowserTestUtils.waitForEvent(tab, "SSTabRestored");
@@ -178,4 +180,3 @@ add_task(async function test_send_all() {
     "Email": EMAIL,
   });
 });
-
diff --git a/browser/base/content/test/webextensions/browser_extension_sideloading.js b/browser/base/content/test/webextensions/browser_extension_sideloading.js
index 84f4b3283a245..6d237c93da581 100644
--- a/browser/base/content/test/webextensions/browser_extension_sideloading.js
+++ b/browser/base/content/test/webextensions/browser_extension_sideloading.js
@@ -133,6 +133,7 @@ add_task(async function() {
   is(gBrowser.currentURI.spec, "about:addons", "Foreground tab is at about:addons");
 
   const VIEW = "addons://list/extension";
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let win = gBrowser.selectedBrowser.contentWindow;
   ok(!win.gViewController.isLoading, "about:addons view is fully loaded");
   is(win.gViewController.currentViewId, VIEW, "about:addons is at extensions list");
@@ -168,6 +169,7 @@ add_task(async function() {
   // Again we should be at the extentions list in about:addons
   is(gBrowser.currentURI.spec, "about:addons", "Foreground tab is at about:addons");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   win = gBrowser.selectedBrowser.contentWindow;
   ok(!win.gViewController.isLoading, "about:addons view is fully loaded");
   is(win.gViewController.currentViewId, VIEW, "about:addons is at extensions list");
diff --git a/browser/components/contextualidentity/test/browser/browser_usercontext.js b/browser/components/contextualidentity/test/browser/browser_usercontext.js
index b60246e49d57e..27fb560369a22 100644
--- a/browser/components/contextualidentity/test/browser/browser_usercontext.js
+++ b/browser/components/contextualidentity/test/browser/browser_usercontext.js
@@ -69,6 +69,7 @@ add_task(async function test() {
     await BrowserTestUtils.browserLoaded(browser);
 
     // get the title
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let title = browser.contentDocument.title.trim().split("|");
 
     // check each item in the title and validate it meets expectatations
diff --git a/browser/components/customizableui/test/browser_947914_button_addons.js b/browser/components/customizableui/test/browser_947914_button_addons.js
index 13007a6896e78..b13d187de6032 100644
--- a/browser/components/customizableui/test/browser_947914_button_addons.js
+++ b/browser/components/customizableui/test/browser_947914_button_addons.js
@@ -24,6 +24,7 @@ add_task(async function() {
   await waitForCondition(() => gBrowser.currentURI &&
                                gBrowser.currentURI.spec == "about:addons");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let addonsPage = gBrowser.selectedBrowser.contentWindow.document.
                             getElementById("addons-page");
   ok(addonsPage, "Add-ons page was opened");
diff --git a/browser/components/preferences/in-content/tests/browser_applications_selection.js b/browser/components/preferences/in-content/tests/browser_applications_selection.js
index e617aea2ff0a0..61591c804744e 100644
--- a/browser/components/preferences/in-content/tests/browser_applications_selection.js
+++ b/browser/components/preferences/in-content/tests/browser_applications_selection.js
@@ -8,6 +8,7 @@ add_task(async function setup() {
   await openPreferencesViaOpenPreferencesAPI("general", { leaveOpen: true });
   info("Preferences page opened on the general pane.");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   await gBrowser.selectedBrowser.contentWindow.promiseLoadHandlersList;
   info("Apps list loaded.");
 
@@ -17,6 +18,7 @@ add_task(async function setup() {
 });
 
 add_task(async function getFeedItem() {
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   win = gBrowser.selectedBrowser.contentWindow;
 
   container = win.document.getElementById("handlersView");
@@ -82,6 +84,7 @@ add_task(async function reselectInternalOptionForFeed() {
 });
 
 add_task(async function sortingCheck() {
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   win = gBrowser.selectedBrowser.contentWindow;
 
   const handlerView = win.document.getElementById("handlersView");
diff --git a/browser/components/preferences/in-content/tests/browser_basic_rebuild_fonts_test.js b/browser/components/preferences/in-content/tests/browser_basic_rebuild_fonts_test.js
index 6e0d6c4babbbf..2cb5ed22aea82 100644
--- a/browser/components/preferences/in-content/tests/browser_basic_rebuild_fonts_test.js
+++ b/browser/components/preferences/in-content/tests/browser_basic_rebuild_fonts_test.js
@@ -6,7 +6,9 @@ registerCleanupFunction(function() {
 
 add_task(async function() {
   await openPreferencesViaOpenPreferencesAPI("general", { leaveOpen: true });
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   await gBrowser.contentWindow.gMainPane._selectDefaultLanguageGroupPromise;
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   var langGroup = Services.prefs.getComplexValue("font.language.group", Ci.nsIPrefLocalizedString).data;
   is(doc.getElementById("font.language.group").value, langGroup,
diff --git a/browser/components/preferences/in-content/tests/browser_bug1018066_resetScrollPosition.js b/browser/components/preferences/in-content/tests/browser_bug1018066_resetScrollPosition.js
index 7487e55e648df..e49c294735eb1 100644
--- a/browser/components/preferences/in-content/tests/browser_bug1018066_resetScrollPosition.js
+++ b/browser/components/preferences/in-content/tests/browser_bug1018066_resetScrollPosition.js
@@ -13,10 +13,12 @@ add_task(async function() {
   window.resizeTo(window.outerWidth, 300);
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneSearch", {leaveOpen: true});
   is(prefs.selectedPane, "paneSearch", "Search pane was selected");
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let mainContent = gBrowser.contentDocument.querySelector(".main-content");
   mainContent.scrollTop = 50;
   is(mainContent.scrollTop, 50, "main-content should be scrolled 50 pixels");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   gBrowser.contentWindow.gotoPref("paneGeneral");
   is(mainContent.scrollTop, 0,
      "Switching to a different category should reset the scroll position");
diff --git a/browser/components/preferences/in-content/tests/browser_bug1020245_openPreferences_to_paneContent.js b/browser/components/preferences/in-content/tests/browser_bug1020245_openPreferences_to_paneContent.js
index 0c83316a15eb4..01ab9c95d229c 100644
--- a/browser/components/preferences/in-content/tests/browser_bug1020245_openPreferences_to_paneContent.js
+++ b/browser/components/preferences/in-content/tests/browser_bug1020245_openPreferences_to_paneContent.js
@@ -1,6 +1,8 @@
 /* Any copyright is dedicated to the Public Domain.
  * http://creativecommons.org/publicdomain/zero/1.0/ */
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 Services.prefs.setBoolPref("browser.preferences.instantApply", true);
 
 registerCleanupFunction(function() {
diff --git a/browser/components/preferences/in-content/tests/browser_bug1184989_prevent_scrolling_when_preferences_flipped.js b/browser/components/preferences/in-content/tests/browser_bug1184989_prevent_scrolling_when_preferences_flipped.js
index ac3dec3d9f11b..e9bbbc6a2bfdf 100644
--- a/browser/components/preferences/in-content/tests/browser_bug1184989_prevent_scrolling_when_preferences_flipped.js
+++ b/browser/components/preferences/in-content/tests/browser_bug1184989_prevent_scrolling_when_preferences_flipped.js
@@ -9,6 +9,7 @@ add_task(async function() {
   const tabURL = getRootDirectory(gTestPath) + "browser_bug1184989_prevent_scrolling_when_preferences_flipped.xul";
 
   await BrowserTestUtils.withNewTab({ gBrowser, url: tabURL }, async function(browser) {
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let doc = browser.contentDocument;
     let container = doc.getElementById("container");
 
@@ -41,6 +42,7 @@ add_task(async function() {
   });
 
   await BrowserTestUtils.withNewTab({ gBrowser, url: "about:preferences#search" }, async function(browser) {
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let doc = browser.contentDocument;
     let container = doc.getElementsByClassName("main-content")[0];
 
diff --git a/browser/components/preferences/in-content/tests/browser_bug410900.js b/browser/components/preferences/in-content/tests/browser_bug410900.js
index 58d1f6c472678..3cdfa52ff1b06 100644
--- a/browser/components/preferences/in-content/tests/browser_bug410900.js
+++ b/browser/components/preferences/in-content/tests/browser_bug410900.js
@@ -22,9 +22,11 @@ function test() {
               getService(Ci.nsIHandlerService);
   hserv.store(info);
 
+  /* eslint-disable mozilla/no-cpows-in-tests */
   openPreferencesViaOpenPreferencesAPI("general", {leaveOpen: true})
   .then(() => gBrowser.selectedBrowser.contentWindow.promiseLoadHandlersList)
   .then(() => runTest(gBrowser.selectedBrowser.contentWindow));
+  /* eslint-enable mozilla/no-cpows-in-tests */
 }
 
 function runTest(win) {
diff --git a/browser/components/preferences/in-content/tests/browser_change_app_handler.js b/browser/components/preferences/in-content/tests/browser_change_app_handler.js
index fe969f8a6a026..8448ab034f0ca 100644
--- a/browser/components/preferences/in-content/tests/browser_change_app_handler.js
+++ b/browser/components/preferences/in-content/tests/browser_change_app_handler.js
@@ -19,6 +19,7 @@ add_task(async function() {
 
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let win = gBrowser.selectedBrowser.contentWindow;
 
   let container = win.document.getElementById("handlersView");
@@ -98,4 +99,3 @@ registerCleanupFunction(function() {
   let infoToModify = gMimeSvc.getFromTypeAndExtension("text/x-test-handler", null);
   gHandlerSvc.remove(infoToModify);
 });
-
diff --git a/browser/components/preferences/in-content/tests/browser_checkspelling.js b/browser/components/preferences/in-content/tests/browser_checkspelling.js
index 4775f12ab4b50..1c27c00f38a97 100644
--- a/browser/components/preferences/in-content/tests/browser_checkspelling.js
+++ b/browser/components/preferences/in-content/tests/browser_checkspelling.js
@@ -6,6 +6,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   let checkbox = doc.querySelector("#checkSpelling");
   is(checkbox.checked,
diff --git a/browser/components/preferences/in-content/tests/browser_cookies_exceptions.js b/browser/components/preferences/in-content/tests/browser_cookies_exceptions.js
index b349193979192..f4644b5226d0e 100644
--- a/browser/components/preferences/in-content/tests/browser_cookies_exceptions.js
+++ b/browser/components/preferences/in-content/tests/browser_cookies_exceptions.js
@@ -328,6 +328,7 @@ var testRunner = {
       });
 
       openPreferencesViaOpenPreferencesAPI("panePrivacy", {leaveOpen: true}).then(function() {
+        // eslint-disable-next-line mozilla/no-cpows-in-tests
         let doc = gBrowser.contentDocument;
         let historyMode = doc.getElementById("historyMode");
         historyMode.value = "custom";
diff --git a/browser/components/preferences/in-content/tests/browser_engines.js b/browser/components/preferences/in-content/tests/browser_engines.js
index 5b248c36de8a3..65eb7b2e3430c 100644
--- a/browser/components/preferences/in-content/tests/browser_engines.js
+++ b/browser/components/preferences/in-content/tests/browser_engines.js
@@ -2,6 +2,7 @@
 add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("search", {leaveOpen: true});
   is(prefs.selectedPane, "paneSearch", "Search pane is selected by default");
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
 
   let tree = doc.querySelector("#engineList");
@@ -23,4 +24,3 @@ add_task(async function() {
 
   await BrowserTestUtils.removeTab(gBrowser.selectedTab);
 });
-
diff --git a/browser/components/preferences/in-content/tests/browser_extension_controlled.js b/browser/components/preferences/in-content/tests/browser_extension_controlled.js
index e8fb5fa364537..0360adc24be70 100644
--- a/browser/components/preferences/in-content/tests/browser_extension_controlled.js
+++ b/browser/components/preferences/in-content/tests/browser_extension_controlled.js
@@ -48,6 +48,7 @@ function waitForMutation(target, opts, cb) {
 
 function waitForMessageChange(messageId, cb) {
   return waitForMutation(
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     gBrowser.contentDocument.getElementById(messageId),
     { attributes: true, attributeFilter: ["hidden"] }, cb);
 }
@@ -62,6 +63,7 @@ function waitForMessageShown(messageId) {
 
 add_task(async function testExtensionControlledHomepage() {
   await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   is(gBrowser.currentURI.spec, "about:preferences#general",
      "#general should be in the URI for about:preferences");
@@ -111,6 +113,7 @@ add_task(async function testExtensionControlledHomepage() {
 
 add_task(async function testPrefLockedHomepage() {
   await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   is(gBrowser.currentURI.spec, "about:preferences#general",
      "#general should be in the URI for about:preferences");
@@ -242,6 +245,7 @@ add_task(async function testPrefLockedHomepage() {
 
 add_task(async function testExtensionControlledNewTab() {
   await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   is(gBrowser.currentURI.spec, "about:preferences#general",
      "#general should be in the URI for about:preferences");
@@ -281,6 +285,7 @@ add_task(async function testExtensionControlledNewTab() {
 add_task(async function testExtensionControlledHomepageUninstalledAddon() {
   async function checkHomepageEnabled() {
     await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let doc = gBrowser.contentDocument;
     is(gBrowser.currentURI.spec, "about:preferences#general",
       "#general should be in the URI for about:preferences");
diff --git a/browser/components/preferences/in-content/tests/browser_homepages_filter_aboutpreferences.js b/browser/components/preferences/in-content/tests/browser_homepages_filter_aboutpreferences.js
index 3bbd1e5bf0073..cee329d138b9c 100644
--- a/browser/components/preferences/in-content/tests/browser_homepages_filter_aboutpreferences.js
+++ b/browser/components/preferences/in-content/tests/browser_homepages_filter_aboutpreferences.js
@@ -2,6 +2,7 @@ add_task(async function testSetHomepageUseCurrent() {
   is(gBrowser.currentURI.spec, "about:blank", "Test starts with about:blank open");
   await BrowserTestUtils.openNewForegroundTab(gBrowser, "about:home");
   await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   is(gBrowser.currentURI.spec, "about:preferences#general",
      "#general should be in the URI for about:preferences");
diff --git a/browser/components/preferences/in-content/tests/browser_layersacceleration.js b/browser/components/preferences/in-content/tests/browser_layersacceleration.js
index 560705466b8cf..8dfa50b815f2e 100644
--- a/browser/components/preferences/in-content/tests/browser_layersacceleration.js
+++ b/browser/components/preferences/in-content/tests/browser_layersacceleration.js
@@ -7,6 +7,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   let checkbox = doc.querySelector("#allowHWAccel");
   is(!checkbox.checked,
diff --git a/browser/components/preferences/in-content/tests/browser_masterpassword.js b/browser/components/preferences/in-content/tests/browser_masterpassword.js
index 6ff68bd87bafb..84a7f87e987d4 100644
--- a/browser/components/preferences/in-content/tests/browser_masterpassword.js
+++ b/browser/components/preferences/in-content/tests/browser_masterpassword.js
@@ -2,6 +2,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("panePrivacy", {leaveOpen: true});
   is(prefs.selectedPane, "panePrivacy", "Privacy pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   // Fake the subdialog and LoginHelper
   let win = doc.defaultView;
diff --git a/browser/components/preferences/in-content/tests/browser_notifications_do_not_disturb.js b/browser/components/preferences/in-content/tests/browser_notifications_do_not_disturb.js
index 59d24d78667b1..42469ec0a9fe1 100644
--- a/browser/components/preferences/in-content/tests/browser_notifications_do_not_disturb.js
+++ b/browser/components/preferences/in-content/tests/browser_notifications_do_not_disturb.js
@@ -11,6 +11,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("panePrivacy", {leaveOpen: true});
   is(prefs.selectedPane, "panePrivacy", "Privacy pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   let notificationsDoNotDisturbBox = doc.getElementById("notificationsDoNotDisturbBox");
   if (notificationsDoNotDisturbBox.hidden) {
diff --git a/browser/components/preferences/in-content/tests/browser_performance.js b/browser/components/preferences/in-content/tests/browser_performance.js
index bccc28728ec37..16f049032be19 100644
--- a/browser/components/preferences/in-content/tests/browser_performance.js
+++ b/browser/components/preferences/in-content/tests/browser_performance.js
@@ -13,6 +13,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   let useRecommendedPerformanceSettings = doc.querySelector("#useRecommendedPerformanceSettings");
 
@@ -78,6 +79,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   let useRecommendedPerformanceSettings = doc.querySelector("#useRecommendedPerformanceSettings");
   let allowHWAccel = doc.querySelector("#allowHWAccel");
@@ -103,6 +105,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   let performanceSettings = doc.querySelector("#performanceSettings");
 
@@ -122,6 +125,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
 
   let performanceSettings = doc.querySelector("#performanceSettings");
@@ -141,6 +145,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
 
   let performanceSettings = doc.querySelector("#performanceSettings");
diff --git a/browser/components/preferences/in-content/tests/browser_performance_e10srollout.js b/browser/components/preferences/in-content/tests/browser_performance_e10srollout.js
index 968b61e9bdff3..6f798ce07151a 100644
--- a/browser/components/preferences/in-content/tests/browser_performance_e10srollout.js
+++ b/browser/components/preferences/in-content/tests/browser_performance_e10srollout.js
@@ -16,6 +16,7 @@ add_task(async function testPrefsAreDefault() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   let useRecommendedPerformanceSettings = doc.querySelector("#useRecommendedPerformanceSettings");
 
@@ -50,6 +51,7 @@ add_task(async function testPrefsSetByUser() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   let performanceSettings = doc.querySelector("#performanceSettings");
   is(performanceSettings.hidden, false, "performance settings section is shown");
diff --git a/browser/components/preferences/in-content/tests/browser_performance_non_e10s.js b/browser/components/preferences/in-content/tests/browser_performance_non_e10s.js
index a3492ef120f63..013c0105c3f8c 100644
--- a/browser/components/preferences/in-content/tests/browser_performance_non_e10s.js
+++ b/browser/components/preferences/in-content/tests/browser_performance_non_e10s.js
@@ -13,6 +13,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   let useRecommendedPerformanceSettings = doc.querySelector("#useRecommendedPerformanceSettings");
 
@@ -66,6 +67,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
   let performanceSettings = doc.querySelector("#performanceSettings");
 
@@ -85,6 +87,7 @@ add_task(async function() {
   let prefs = await openPreferencesViaOpenPreferencesAPI("paneGeneral", {leaveOpen: true});
   is(prefs.selectedPane, "paneGeneral", "General pane was selected");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = gBrowser.contentDocument;
 
   let performanceSettings = doc.querySelector("#performanceSettings");
diff --git a/browser/components/preferences/in-content/tests/browser_permissions_urlFieldHidden.js b/browser/components/preferences/in-content/tests/browser_permissions_urlFieldHidden.js
index 299452649fc2a..89fe4983877f7 100644
--- a/browser/components/preferences/in-content/tests/browser_permissions_urlFieldHidden.js
+++ b/browser/components/preferences/in-content/tests/browser_permissions_urlFieldHidden.js
@@ -4,6 +4,7 @@ const PERMISSIONS_URL = "chrome://browser/content/preferences/permissions.xul";
 
 add_task(async function urlFieldVisibleForPopupPermissions(finish) {
   await openPreferencesViaOpenPreferencesAPI("panePrivacy", {leaveOpen: true});
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let win = gBrowser.selectedBrowser.contentWindow;
   let doc = win.document;
   let popupPolicyCheckbox = doc.getElementById("popupPolicy");
diff --git a/browser/components/preferences/in-content/tests/browser_sanitizeOnShutdown_prefLocked.js b/browser/components/preferences/in-content/tests/browser_sanitizeOnShutdown_prefLocked.js
index 5332da31d28c8..53f9bf4f10780 100644
--- a/browser/components/preferences/in-content/tests/browser_sanitizeOnShutdown_prefLocked.js
+++ b/browser/components/preferences/in-content/tests/browser_sanitizeOnShutdown_prefLocked.js
@@ -8,6 +8,7 @@ function switchToCustomHistoryMode(doc) {
 }
 
 function testPrefStateMatchesLockedState() {
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let win = gBrowser.contentWindow;
   let doc = win.document;
   switchToCustomHistoryMode(doc);
diff --git a/browser/components/preferences/in-content/tests/browser_search_within_preferences_1.js b/browser/components/preferences/in-content/tests/browser_search_within_preferences_1.js
index 2a85dec83af42..42056a439ab62 100644
--- a/browser/components/preferences/in-content/tests/browser_search_within_preferences_1.js
+++ b/browser/components/preferences/in-content/tests/browser_search_within_preferences_1.js
@@ -3,6 +3,8 @@
  * This file contains tests for the Preferences search bar.
  */
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 requestLongerTimeout(6);
 
 /**
diff --git a/browser/components/preferences/in-content/tests/browser_search_within_preferences_2.js b/browser/components/preferences/in-content/tests/browser_search_within_preferences_2.js
index 4f6e294dd33ca..223d2c2df7ecf 100644
--- a/browser/components/preferences/in-content/tests/browser_search_within_preferences_2.js
+++ b/browser/components/preferences/in-content/tests/browser_search_within_preferences_2.js
@@ -3,6 +3,8 @@
  * This file contains tests for the Preferences search bar.
  */
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 /**
  * Enabling searching functionality. Will display search bar from this testcase forward.
  */
diff --git a/browser/components/preferences/in-content/tests/browser_search_within_preferences_command.js b/browser/components/preferences/in-content/tests/browser_search_within_preferences_command.js
index 0e864b0f7c66c..38b376d833199 100644
--- a/browser/components/preferences/in-content/tests/browser_search_within_preferences_command.js
+++ b/browser/components/preferences/in-content/tests/browser_search_within_preferences_command.js
@@ -1,5 +1,7 @@
 "use strict";
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 /**
  * Test for "command" event on search input (when user clicks the x button)
  */
diff --git a/browser/components/preferences/in-content/tests/browser_security-1.js b/browser/components/preferences/in-content/tests/browser_security-1.js
index 3d3f9482e7058..518224daddff7 100644
--- a/browser/components/preferences/in-content/tests/browser_security-1.js
+++ b/browser/components/preferences/in-content/tests/browser_security-1.js
@@ -52,6 +52,7 @@ add_task(async function() {
 
     // scroll the checkbox into the viewport and click checkbox
     checkbox.scrollIntoView();
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     EventUtils.synthesizeMouseAtCenter(checkbox, {}, gBrowser.selectedBrowser.contentWindow);
 
     // check that both settings are now turned on or off
diff --git a/browser/components/preferences/in-content/tests/browser_security-2.js b/browser/components/preferences/in-content/tests/browser_security-2.js
index f8ad2794a9395..89187d422b4c9 100644
--- a/browser/components/preferences/in-content/tests/browser_security-2.js
+++ b/browser/components/preferences/in-content/tests/browser_security-2.js
@@ -49,6 +49,7 @@ add_task(async function() {
 
     // scroll the checkbox into view, otherwise the synthesizeMouseAtCenter will be ignored, and click it
     checkbox.scrollIntoView();
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     EventUtils.synthesizeMouseAtCenter(checkbox, {}, gBrowser.selectedBrowser.contentWindow);
 
     // check that setting is now turned on or off
@@ -88,6 +89,7 @@ add_task(async function() {
 
     // scroll the checkbox into view, otherwise the synthesizeMouseAtCenter will be ignored, and click it
     checkbox.scrollIntoView();
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     EventUtils.synthesizeMouseAtCenter(checkbox, {}, gBrowser.selectedBrowser.contentWindow);
 
     // check that both settings are now turned on or off
diff --git a/browser/components/preferences/in-content/tests/browser_siteData.js b/browser/components/preferences/in-content/tests/browser_siteData.js
index 71ce20b836ebd..36a960c9dc0a9 100644
--- a/browser/components/preferences/in-content/tests/browser_siteData.js
+++ b/browser/components/preferences/in-content/tests/browser_siteData.js
@@ -102,6 +102,7 @@ add_task(async function() {
 
   // Open a test site which would save into quota manager
   await BrowserTestUtils.openNewForegroundTab(gBrowser, TEST_QUOTA_USAGE_URL);
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   await waitForEvent(gBrowser.selectedBrowser.contentWindow, "test-indexedDB-done");
   await BrowserTestUtils.removeTab(gBrowser.selectedTab);
 
@@ -184,6 +185,7 @@ add_task(async function() {
   addPersistentStoragePerm(TEST_QUOTA_USAGE_ORIGIN);
 
   await BrowserTestUtils.openNewForegroundTab(gBrowser, TEST_QUOTA_USAGE_URL);
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   await waitForEvent(gBrowser.selectedBrowser.contentWindow, "test-indexedDB-done");
   await BrowserTestUtils.removeTab(gBrowser.selectedTab);
 
diff --git a/browser/components/preferences/in-content/tests/browser_siteData2.js b/browser/components/preferences/in-content/tests/browser_siteData2.js
index b814302a2df0e..6653d8e9fc198 100644
--- a/browser/components/preferences/in-content/tests/browser_siteData2.js
+++ b/browser/components/preferences/in-content/tests/browser_siteData2.js
@@ -2,6 +2,8 @@
 const { SiteDataManager } = Cu.import("resource:///modules/SiteDataManager.jsm", {});
 const REMOVE_DIALOG_URL = "chrome://browser/content/preferences/siteDataRemoveSelected.xul";
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 function promiseSettingsDialogClose() {
   return new Promise(resolve => {
     let win = gBrowser.selectedBrowser.contentWindow;
diff --git a/browser/components/preferences/in-content/tests/browser_siteData3.js b/browser/components/preferences/in-content/tests/browser_siteData3.js
index 2fe37a48d0d59..cd70e3cd9d9b0 100644
--- a/browser/components/preferences/in-content/tests/browser_siteData3.js
+++ b/browser/components/preferences/in-content/tests/browser_siteData3.js
@@ -81,6 +81,7 @@ add_task(async function() {
   await openPreferencesViaOpenPreferencesAPI("privacy", { leaveOpen: true });
   await updatedPromise;
   await openSiteDataSettingsDialog();
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let win = gBrowser.selectedBrowser.contentWindow;
   let dialogFrame = win.gSubDialog._topDialog._frame;
   let frameDoc = dialogFrame.contentDocument;
diff --git a/browser/components/search/test/browser_aboutSearchReset.js b/browser/components/search/test/browser_aboutSearchReset.js
index 4504495f8045b..5f811de945dd9 100644
--- a/browser/components/search/test/browser_aboutSearchReset.js
+++ b/browser/components/search/test/browser_aboutSearchReset.js
@@ -61,6 +61,7 @@ var gTests = [
     rawEngine.setAttr("loadPathHash", "broken");
 
     let loadPromise = promiseStoppedLoad(expectedURL);
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     gBrowser.contentDocument.getElementById("searchResetKeepCurrent").click();
     await loadPromise;
 
@@ -78,6 +79,7 @@ var gTests = [
   async run() {
     let currentEngine = Services.search.currentEngine;
     let originalEngine = Services.search.originalDefaultEngine;
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     let doc = gBrowser.contentDocument;
     let defaultEngineSpan = doc.getElementById("defaultEngine");
     is(defaultEngineSpan.textContent, originalEngine.name,
@@ -107,6 +109,7 @@ var gTests = [
     let loadPromise = BrowserTestUtils.browserLoaded(gBrowser.selectedBrowser,
                                                      false,
                                                      "about:preferences");
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     gBrowser.contentDocument.getElementById("linkSettingsPage").click();
     await loadPromise;
 
diff --git a/browser/components/sessionstore/test/browser_480893.js b/browser/components/sessionstore/test/browser_480893.js
index c157f7b6de0ac..32f55aceed9e7 100644
--- a/browser/components/sessionstore/test/browser_480893.js
+++ b/browser/components/sessionstore/test/browser_480893.js
@@ -16,6 +16,7 @@ add_task(async function() {
   let browser = tab.linkedBrowser;
   await BrowserTestUtils.browserLoaded(browser, false, "about:sessionrestore");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = browser.contentDocument;
 
   // Click on the "Close" button after about:sessionrestore is loaded.
@@ -35,6 +36,7 @@ add_task(async function() {
 
   browser.loadURI("about:sessionrestore");
   await BrowserTestUtils.browserLoaded(browser, false, "about:sessionrestore");
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   doc = browser.contentDocument;
 
   // Click on the "Close" button after about:sessionrestore is loaded.
diff --git a/browser/components/sessionstore/test/browser_590563.js b/browser/components/sessionstore/test/browser_590563.js
index c0be7c7b6ca62..e1c7ed0473a02 100644
--- a/browser/components/sessionstore/test/browser_590563.js
+++ b/browser/components/sessionstore/test/browser_590563.js
@@ -32,6 +32,7 @@ function test() {
 
 async function middleClickTest(win) {
   let browser = win.gBrowser.selectedBrowser;
+  /* eslint-disable mozilla/no-cpows-in-tests */
   let tabsToggle = browser.contentDocument.getElementById("tabsToggle");
   EventUtils.synthesizeMouseAtCenter(tabsToggle, { button: 0 }, browser.contentWindow);
   let treeContainer = browser.contentDocument.querySelector(".tree-container");
@@ -39,6 +40,7 @@ async function middleClickTest(win) {
 
   let tree = browser.contentDocument.getElementById("tabList");
   is(tree.view.rowCount, 3, "There should be three items");
+  /* eslint-enable mozilla/no-cpows-in-tests */
 
   // click on the first tab item
   var rect = tree.treeBoxObject.getCoordsForCellItem(1, tree.columns[1], "text");
diff --git a/browser/components/sessionstore/test/browser_705597.js b/browser/components/sessionstore/test/browser_705597.js
index f560d735a6e81..4c50b8ac08a98 100644
--- a/browser/components/sessionstore/test/browser_705597.js
+++ b/browser/components/sessionstore/test/browser_705597.js
@@ -47,6 +47,7 @@ function test() {
       });
 
       // Create a dynamic subframe.
+      // eslint-disable-next-line mozilla/no-cpows-in-tests
       let doc = browser.contentDocument;
       let iframe = doc.createElement("iframe");
       doc.body.appendChild(iframe);
diff --git a/browser/components/sessionstore/test/browser_707862.js b/browser/components/sessionstore/test/browser_707862.js
index 527743f871c9a..ad78799b17b63 100644
--- a/browser/components/sessionstore/test/browser_707862.js
+++ b/browser/components/sessionstore/test/browser_707862.js
@@ -46,6 +46,7 @@ function test() {
       });
 
       // Create a dynamic subframe.
+      // eslint-disable-next-line mozilla/no-cpows-in-tests
       let doc = browser.contentDocument;
       let iframe = doc.createElement("iframe");
       doc.body.appendChild(iframe);
diff --git a/browser/components/sessionstore/test/browser_aboutSessionRestore.js b/browser/components/sessionstore/test/browser_aboutSessionRestore.js
index 72289db6cd16a..c1e6e394d0792 100644
--- a/browser/components/sessionstore/test/browser_aboutSessionRestore.js
+++ b/browser/components/sessionstore/test/browser_aboutSessionRestore.js
@@ -29,6 +29,7 @@ add_task(async function() {
 
   ok(gBrowser.tabs.length > 1, "we have more than one tab");
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let view = browser.contentDocument.getElementById("tabList").view;
   ok(view.isContainer(0), "first entry is the window");
   is(view.getCellProperties(1, { id: "title" }), "icon",
diff --git a/browser/components/sessionstore/test/browser_crashedTabs.js b/browser/components/sessionstore/test/browser_crashedTabs.js
index 2df5ebb302bfb..b1db20c620a1c 100644
--- a/browser/components/sessionstore/test/browser_crashedTabs.js
+++ b/browser/components/sessionstore/test/browser_crashedTabs.js
@@ -390,6 +390,7 @@ add_task(async function test_hide_restore_all_button() {
   // Crash the tab
   await BrowserTestUtils.crashBrowser(browser);
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = browser.contentDocument;
   let restoreAllButton = doc.getElementById("restoreAll");
   let restoreOneButton = doc.getElementById("restoreTab");
@@ -420,6 +421,7 @@ add_task(async function test_hide_restore_all_button() {
   await BrowserTestUtils.crashBrowser(browser);
   await otherBrowserReady;
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   doc = browser.contentDocument;
   restoreAllButton = doc.getElementById("restoreAll");
   restoreOneButton = doc.getElementById("restoreTab");
diff --git a/browser/components/sessionstore/test/browser_swapDocShells.js b/browser/components/sessionstore/test/browser_swapDocShells.js
index 77b91563e9d6d..d6d11f9c8816c 100644
--- a/browser/components/sessionstore/test/browser_swapDocShells.js
+++ b/browser/components/sessionstore/test/browser_swapDocShells.js
@@ -26,6 +26,7 @@ function promiseDelayedStartupFinished(win) {
 function promiseBrowserHasURL(browser, url) {
   let promise = Promise.resolve();
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   if (browser.contentDocument.readyState === "complete" &&
       browser.currentURI.spec === url) {
     return promise;
diff --git a/browser/extensions/formautofill/.eslintrc.js b/browser/extensions/formautofill/.eslintrc.js
index de11fdf826b61..1a94202cc52a5 100644
--- a/browser/extensions/formautofill/.eslintrc.js
+++ b/browser/extensions/formautofill/.eslintrc.js
@@ -5,7 +5,6 @@ module.exports = {
     // Rules from the mozilla plugin
     "mozilla/balanced-listeners": "error",
     "mozilla/no-aArgs": "error",
-    "mozilla/no-cpows-in-tests": "error",
     "mozilla/var-only-at-top-level": "error",
 
     "valid-jsdoc": ["error", {
diff --git a/browser/extensions/onboarding/test/browser/browser_onboarding_tourset.js b/browser/extensions/onboarding/test/browser/browser_onboarding_tourset.js
index 0e3ccaa8b4a72..28ed8db582df8 100644
--- a/browser/extensions/onboarding/test/browser/browser_onboarding_tourset.js
+++ b/browser/extensions/onboarding/test/browser/browser_onboarding_tourset.js
@@ -13,6 +13,7 @@ add_task(async function test_onboarding_default_new_tourset() {
   await BrowserTestUtils.synthesizeMouseAtCenter("#onboarding-overlay-button", {}, tab.linkedBrowser);
   await promiseOnboardingOverlayOpened(tab.linkedBrowser);
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = content && content.document;
   let doms = doc.querySelectorAll(".onboarding-tour-item");
   is(doms.length, TOUR_IDs.length, "has exact tour numbers");
@@ -43,6 +44,7 @@ add_task(async function test_onboarding_custom_new_tourset() {
   await BrowserTestUtils.synthesizeMouseAtCenter("#onboarding-overlay-button", {}, tab.linkedBrowser);
   await promiseOnboardingOverlayOpened(tab.linkedBrowser);
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = content && content.document;
   let doms = doc.querySelectorAll(".onboarding-tour-item");
   is(doms.length, CUSTOM_NEW_TOURs.length, "has exact tour numbers");
@@ -72,6 +74,7 @@ add_task(async function test_onboarding_custom_update_tourset() {
   await BrowserTestUtils.synthesizeMouseAtCenter("#onboarding-overlay-button", {}, tab.linkedBrowser);
   await promiseOnboardingOverlayOpened(tab.linkedBrowser);
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   let doc = content && content.document;
   let doms = doc.querySelectorAll(".onboarding-tour-item");
   is(doms.length, CUSTOM_UPDATE_TOURs.length, "has exact tour numbers");
diff --git a/browser/extensions/shield-recipe-client/test/browser/browser_about_preferences.js b/browser/extensions/shield-recipe-client/test/browser/browser_about_preferences.js
index e350b84eda80c..3b696d6ce4277 100644
--- a/browser/extensions/shield-recipe-client/test/browser/browser_about_preferences.js
+++ b/browser/extensions/shield-recipe-client/test/browser/browser_about_preferences.js
@@ -1,5 +1,7 @@
 "use strict";
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 Cu.import("resource://gre/modules/Services.jsm", this);
 
 const OPT_OUT_PREF = "app.shield.optoutstudies.enabled";
diff --git a/browser/extensions/shield-recipe-client/test/browser/browser_about_studies.js b/browser/extensions/shield-recipe-client/test/browser/browser_about_studies.js
index 0de76300ae87c..a70b7595fcf3a 100644
--- a/browser/extensions/shield-recipe-client/test/browser/browser_about_studies.js
+++ b/browser/extensions/shield-recipe-client/test/browser/browser_about_studies.js
@@ -14,6 +14,7 @@ function withAboutStudies(testFunc) {
 decorate_task(
   withAboutStudies,
   async function testAboutStudiesWorks(browser) {
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     ok(browser.contentDocument.getElementById("app"), "App element was found");
   }
 );
@@ -50,11 +51,13 @@ decorate_task(
       });
     });
 
+    /* eslint-disable mozilla/no-cpows-in-tests */
     if (gBrowser.contentDocument.readyState !== "complete") {
       await BrowserTestUtils.waitForEvent(gBrowser.contentWindow, "load");
     }
 
     const location = gBrowser.contentWindow.location.href;
+    /* eslint-enable mozilla/no-cpows-in-tests */
     is(
       location,
       "about:preferences#privacy",
diff --git a/toolkit/components/extensions/.eslintrc.js b/toolkit/components/extensions/.eslintrc.js
index 62dbf90b36d0d..fc3cce83d992f 100644
--- a/toolkit/components/extensions/.eslintrc.js
+++ b/toolkit/components/extensions/.eslintrc.js
@@ -23,7 +23,6 @@ module.exports = {
     // Rules from the mozilla plugin
     "mozilla/balanced-listeners": "error",
     "mozilla/no-aArgs": "error",
-    "mozilla/no-cpows-in-tests": "error",
     "mozilla/var-only-at-top-level": "error",
 
     "valid-jsdoc": ["error", {
diff --git a/toolkit/components/narrate/test/browser_narrate.js b/toolkit/components/narrate/test/browser_narrate.js
index 4c0882429e19f..e461b94260898 100644
--- a/toolkit/components/narrate/test/browser_narrate.js
+++ b/toolkit/components/narrate/test/browser_narrate.js
@@ -4,6 +4,8 @@
 
 "use strict";
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 registerCleanupFunction(teardown);
 
 add_task(async function testNarrate() {
diff --git a/toolkit/components/narrate/test/browser_narrate_language.js b/toolkit/components/narrate/test/browser_narrate_language.js
index 0d73db4054e7c..610e1721f7899 100644
--- a/toolkit/components/narrate/test/browser_narrate_language.js
+++ b/toolkit/components/narrate/test/browser_narrate_language.js
@@ -4,6 +4,8 @@
 
 "use strict";
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 registerCleanupFunction(teardown);
 
 add_task(async function testVoiceselectDropdownAutoclose() {
diff --git a/toolkit/components/narrate/test/browser_voiceselect.js b/toolkit/components/narrate/test/browser_voiceselect.js
index b015fcc95c0c7..9f255d939a6ac 100644
--- a/toolkit/components/narrate/test/browser_voiceselect.js
+++ b/toolkit/components/narrate/test/browser_voiceselect.js
@@ -4,6 +4,8 @@
 
 "use strict";
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 registerCleanupFunction(teardown);
 
 add_task(async function testVoiceselectDropdownAutoclose() {
diff --git a/toolkit/components/narrate/test/browser_word_highlight.js b/toolkit/components/narrate/test/browser_word_highlight.js
index e37ed4104dfcb..beb000fcf90f5 100644
--- a/toolkit/components/narrate/test/browser_word_highlight.js
+++ b/toolkit/components/narrate/test/browser_word_highlight.js
@@ -4,6 +4,8 @@
 
 "use strict";
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 registerCleanupFunction(teardown);
 
 add_task(async function testNarrate() {
diff --git a/toolkit/components/payments/.eslintrc.js b/toolkit/components/payments/.eslintrc.js
index c0e3b4a22f4df..e3d9334144aa3 100644
--- a/toolkit/components/payments/.eslintrc.js
+++ b/toolkit/components/payments/.eslintrc.js
@@ -3,7 +3,6 @@
 module.exports = {
   rules: {
     "mozilla/balanced-listeners": "error",
-    "mozilla/no-cpows-in-tests": "error",
     "mozilla/var-only-at-top-level": "error",
 
     "array-bracket-spacing": ["error", "never"],
diff --git a/toolkit/components/satchel/.eslintrc.js b/toolkit/components/satchel/.eslintrc.js
index c0e3b4a22f4df..e3d9334144aa3 100644
--- a/toolkit/components/satchel/.eslintrc.js
+++ b/toolkit/components/satchel/.eslintrc.js
@@ -3,7 +3,6 @@
 module.exports = {
   rules: {
     "mozilla/balanced-listeners": "error",
-    "mozilla/no-cpows-in-tests": "error",
     "mozilla/var-only-at-top-level": "error",
 
     "array-bracket-spacing": ["error", "never"],
diff --git a/toolkit/components/viewsource/test/browser/browser_bug699356.js b/toolkit/components/viewsource/test/browser/browser_bug699356.js
index e55c4cf205179..6ffbe7798b4a3 100644
--- a/toolkit/components/viewsource/test/browser/browser_bug699356.js
+++ b/toolkit/components/viewsource/test/browser/browser_bug699356.js
@@ -10,6 +10,7 @@ function test() {
     let gBrowser = aWindow.gBrowser;
     let docEl = aWindow.document.documentElement;
 
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     is(gBrowser.contentDocument.title, source, "Correct document title");
     is(docEl.getAttribute("title"),
       "Source of: " + source + ("nsILocalFileMac" in Components.interfaces ? "" : " - " + docEl.getAttribute("titlemodifier")),
diff --git a/toolkit/content/tests/browser/browser_save_resend_postdata.js b/toolkit/content/tests/browser/browser_save_resend_postdata.js
index 6006574ebfc91..8177004fbb39e 100644
--- a/toolkit/content/tests/browser/browser_save_resend_postdata.js
+++ b/toolkit/content/tests/browser/browser_save_resend_postdata.js
@@ -27,6 +27,7 @@ function test() {
     // Submit the form in the outer page, then wait for both the outer
     // document and the inner frame to be loaded again.
     gBrowser.addEventListener("DOMContentLoaded", handleOuterSubmit);
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     gBrowser.contentDocument.getElementById("postForm").submit();
   });
 
@@ -39,6 +40,7 @@ function test() {
 
     gBrowser.removeEventListener("DOMContentLoaded", handleOuterSubmit);
 
+    // eslint-disable-next-line mozilla/no-cpows-in-tests
     innerFrame = gBrowser.contentDocument.getElementById("innerFrame");
 
     // Submit the form in the inner page.
diff --git a/toolkit/mozapps/extensions/test/browser/browser_bug562797.js b/toolkit/mozapps/extensions/test/browser/browser_bug562797.js
index 8ca9af0bbae2c..baff777926992 100644
--- a/toolkit/mozapps/extensions/test/browser/browser_bug562797.js
+++ b/toolkit/mozapps/extensions/test/browser/browser_bug562797.js
@@ -3,6 +3,7 @@
  */
 
 /* eslint max-nested-callbacks: ["warn", 12] */
+/* eslint-disable mozilla/no-cpows-in-tests */
 
 /**
  * Tests that history navigation works for the add-ons manager.
diff --git a/toolkit/mozapps/extensions/test/browser/browser_discovery.js b/toolkit/mozapps/extensions/test/browser/browser_discovery.js
index 9c224ef9956ec..b1885ddd6103c 100644
--- a/toolkit/mozapps/extensions/test/browser/browser_discovery.js
+++ b/toolkit/mozapps/extensions/test/browser/browser_discovery.js
@@ -174,6 +174,7 @@ function clickLink(aId, aCallback) {
     aCallback();
   };
 
+  // eslint-disable-next-line mozilla/no-cpows-in-tests
   var link = browser.contentDocument.getElementById(aId);
   EventUtils.sendMouseEvent({type: "click"}, link);
 
diff --git a/toolkit/mozapps/extensions/test/browser/browser_discovery_install.js b/toolkit/mozapps/extensions/test/browser/browser_discovery_install.js
index 6630baa1471eb..ac4a71291052c 100644
--- a/toolkit/mozapps/extensions/test/browser/browser_discovery_install.js
+++ b/toolkit/mozapps/extensions/test/browser/browser_discovery_install.js
@@ -2,6 +2,8 @@
  * http://creativecommons.org/publicdomain/zero/1.0/
  */
 
+/* eslint-disable mozilla/no-cpows-in-tests */
+
 // Tests that the discovery view can install add-ons correctly
 
 const MAIN_URL = "https://example.com/" + RELATIVE_DIR + "discovery_install.html";
diff --git a/tools/lint/eslint/eslint-plugin-mozilla/lib/configs/browser-test.js b/tools/lint/eslint/eslint-plugin-mozilla/lib/configs/browser-test.js
index 60c610fed8b1d..54a3085c178e2 100644
--- a/tools/lint/eslint/eslint-plugin-mozilla/lib/configs/browser-test.js
+++ b/tools/lint/eslint/eslint-plugin-mozilla/lib/configs/browser-test.js
@@ -61,6 +61,7 @@ module.exports = {
     "mozilla/import-content-task-globals": "error",
     "mozilla/import-headjs-globals": "error",
     "mozilla/mark-test-function-used": "error",
-    "mozilla/no-arbitrary-setTimeout": "error"
+    "mozilla/no-arbitrary-setTimeout": "error",
+    "mozilla/no-cpows-in-tests": "error"
   }
 };