diff --git a/toolkit/components/extensions/ExtensionXPCShellUtils.jsm b/toolkit/components/extensions/ExtensionXPCShellUtils.jsm
index e6c1c5c117b5..6851a018bf0b 100644
--- a/toolkit/components/extensions/ExtensionXPCShellUtils.jsm
+++ b/toolkit/components/extensions/ExtensionXPCShellUtils.jsm
@@ -910,6 +910,14 @@ var ExtensionTestUtils = {
       "services.settings.server",
       "http://localhost:7777/remote-settings-dummy/v1"
     );
+    // Make sure that loading the default settings for url-classifier-skip-urls
+    // doesn't interfere with running our tests while IDB operations are in
+    // flight by overriding the default remote settings bucket pref name to
+    // ensure that the IDB database isn't created in the first place.
+    Services.prefs.setStringPref(
+      "services.settings.default_bucket",
+      "nonexistent-bucket-foo"
+    );
   },
 
   addonManagerStarted: false,
diff --git a/toolkit/components/extensions/test/xpcshell/test_proxy_userContextId.js b/toolkit/components/extensions/test/xpcshell/test_proxy_userContextId.js
index 86cab19ae672..a165ad7c1894 100644
--- a/toolkit/components/extensions/test/xpcshell/test_proxy_userContextId.js
+++ b/toolkit/components/extensions/test/xpcshell/test_proxy_userContextId.js
@@ -17,6 +17,9 @@ add_task(async function test_userContextId_proxy_onRequest() {
     background() {
       browser.proxy.onRequest.addListener(
         async details => {
+          if (details.url != "http://example.com/dummy") {
+            return;
+          }
           browser.test.assertEq(
             details.cookieStoreId,
             "firefox-container-2",