diff --git a/devtools/shared/commands/resource/tests/browser.ini b/devtools/shared/commands/resource/tests/browser.ini
index 543b5a4f96a3..23a26bad1140 100644
--- a/devtools/shared/commands/resource/tests/browser.ini
+++ b/devtools/shared/commands/resource/tests/browser.ini
@@ -12,7 +12,9 @@ support-files =
   network_document.html
   early_console_document.html
   fission_document.html
+  fission_document_workers.html
   fission_iframe.html
+  fission_iframe_workers.html
   service-worker-sources.js
   sources.html
   sources.js
diff --git a/devtools/shared/commands/resource/tests/browser_resources_console_messages.js b/devtools/shared/commands/resource/tests/browser_resources_console_messages.js
index 6fdb3b889d41..84c97a39400d 100644
--- a/devtools/shared/commands/resource/tests/browser_resources_console_messages.js
+++ b/devtools/shared/commands/resource/tests/browser_resources_console_messages.js
@@ -47,12 +47,6 @@ async function testTabConsoleMessagesResources(executeInIframe) {
   const onRuntimeDone = new Promise(resolve => (runtimeDoneResolve = resolve));
   const onAvailable = resources => {
     for (const resource of resources) {
-      if (resource.message.arguments?.[0] === "[WORKER] started") {
-        // XXX Ignore message from workers as we can't know when they're logged, and we
-        // have a dedicated test for them (browser_resources_console_messages_workers.js).
-        continue;
-      }
-
       is(
         resource.resourceType,
         resourceCommand.TYPES.CONSOLE_MESSAGE,
@@ -105,12 +99,6 @@ async function testTabConsoleMessagesResources(executeInIframe) {
 
   targetCommand.destroy();
   await client.close();
-
-  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
-    // registrationPromise is set by the test page.
-    const registration = await content.wrappedJSObject.registrationPromise;
-    registration.unregister();
-  });
 }
 
 async function testTabConsoleMessagesResourcesWithIgnoreExistingResources(
@@ -178,12 +166,6 @@ async function testTabConsoleMessagesResourcesWithIgnoreExistingResources(
 
   targetCommand.destroy();
   await client.close();
-
-  await SpecialPowers.spawn(tab.linkedBrowser, [], async () => {
-    // registrationPromise is set by the test page.
-    const registration = await content.wrappedJSObject.registrationPromise;
-    registration.unregister();
-  });
 }
 
 async function logExistingMessages(browser, executeInIframe) {
diff --git a/devtools/shared/commands/resource/tests/browser_resources_console_messages_navigation.js b/devtools/shared/commands/resource/tests/browser_resources_console_messages_navigation.js
index 07c2d9b40d79..4d1b179dc51e 100644
--- a/devtools/shared/commands/resource/tests/browser_resources_console_messages_navigation.js
+++ b/devtools/shared/commands/resource/tests/browser_resources_console_messages_navigation.js
@@ -35,13 +35,7 @@ async function testCrossProcessTabNavigation(browser, resourceCommand) {
   const onConsoleLogsComplete = new Promise(resolve => (doneResolve = resolve));
 
   const onAvailable = resources => {
-    messages.push(
-      // Ignore all unexpected messages from workers as they are not
-      // useful here and they are tested elsewhere.
-      ...resources.filter(
-        r => !r.message.arguments[0].startsWith("[WORKER] started")
-      )
-    );
+    messages.push(...resources);
     if (messages.length == 2) {
       doneResolve();
     }
diff --git a/devtools/shared/commands/resource/tests/browser_resources_console_messages_workers.js b/devtools/shared/commands/resource/tests/browser_resources_console_messages_workers.js
index 698882b53a5e..2188b6de1b82 100644
--- a/devtools/shared/commands/resource/tests/browser_resources_console_messages_workers.js
+++ b/devtools/shared/commands/resource/tests/browser_resources_console_messages_workers.js
@@ -5,9 +5,9 @@
 
 // Test the ResourceCommand API around CONSOLE_MESSAGE in workers
 
-const FISSION_TEST_URL = URL_ROOT_SSL + "fission_document.html";
+const FISSION_TEST_URL = URL_ROOT_SSL + "fission_document_workers.html";
 const WORKER_FILE = "test_worker.js";
-const IFRAME_FILE = `${URL_ROOT_ORG_SSL}fission_iframe.html`;
+const IFRAME_FILE = `${URL_ROOT_ORG_SSL}fission_iframe_workers.html`;
 
 add_task(async function() {
   // Set the following pref to false as it's the one that enables direct connection
diff --git a/devtools/shared/commands/resource/tests/browser_resources_getAllResources.js b/devtools/shared/commands/resource/tests/browser_resources_getAllResources.js
index 82663e011fb9..cbcebbecb4ee 100644
--- a/devtools/shared/commands/resource/tests/browser_resources_getAllResources.js
+++ b/devtools/shared/commands/resource/tests/browser_resources_getAllResources.js
@@ -35,7 +35,20 @@ add_task(async function() {
   info("Check the resources after some resources are available");
   const messages = ["a", "b", "c"];
   await logMessages(tab.linkedBrowser, messages);
-  await waitUntil(() => availableResources.length >= messages.length);
+
+  try {
+    await waitFor(() => availableResources.length === messages.length);
+  } catch (e) {
+    ok(
+      false,
+      `Didn't receive the expected number of resources. Got ${
+        availableResources.length
+      }, expected ${messages.length} - ${availableResources
+        .map(r => r.message.arguments[0])
+        .join(" - ")}`
+    );
+  }
+
   assertResources(
     resourceCommand.getAllResources(resourceCommand.TYPES.CONSOLE_MESSAGE),
     availableResources
@@ -55,12 +68,27 @@ add_task(async function() {
   );
 
   info("Append some resources again to test unwatching");
+  const newMessages = ["d", "e", "f"];
   await logMessages(tab.linkedBrowser, messages);
-  await waitUntil(
-    () =>
-      resourceCommand.getAllResources(resourceCommand.TYPES.CONSOLE_MESSAGE)
-        .length === messages.length
-  );
+  try {
+    await waitFor(
+      () =>
+        resourceCommand.getAllResources(resourceCommand.TYPES.CONSOLE_MESSAGE)
+          .length === newMessages.length
+    );
+  } catch (e) {
+    const resources = resourceCommand.getAllResources(
+      resourceCommand.TYPES.CONSOLE_MESSAGE
+    );
+    ok(
+      false,
+      `Didn't receive the expected number of resources. Got ${
+        resources.length
+      }, expected ${messages.length} - ${resources
+        .map(r => r.message.arguments.join(" | "))
+        .join(" - ")}`
+    );
+  }
 
   info("Check the resources after unwatching");
   resourceCommand.unwatchResources([resourceCommand.TYPES.CONSOLE_MESSAGE], {
@@ -90,8 +118,8 @@ function assertResources(resources, expectedResources) {
 }
 
 function logMessages(browser, messages) {
-  return ContentTask.spawn(browser, { messages }, args => {
-    for (const message of args.messages) {
+  return SpecialPowers.spawn(browser, [messages], innerMessages => {
+    for (const message of innerMessages) {
       content.console.log(message);
     }
   });
diff --git a/devtools/shared/commands/resource/tests/browser_resources_target_switching.js b/devtools/shared/commands/resource/tests/browser_resources_target_switching.js
index a178fc64fba1..ff075c4480b6 100644
--- a/devtools/shared/commands/resource/tests/browser_resources_target_switching.js
+++ b/devtools/shared/commands/resource/tests/browser_resources_target_switching.js
@@ -28,13 +28,7 @@ add_task(async function() {
   );
   const availableResources = [];
   const onAvailable = resources => {
-    // Ignore message coming from shared worker started by previous tests and
-    // logging late a console message
-    resources
-      .filter(r => {
-        return !r.message.arguments[0].startsWith("[WORKER] started");
-      })
-      .map(r => availableResources.push(r));
+    availableResources.push(...resources);
   };
   await resourceCommand.watchResources([CONSOLE_MESSAGE], { onAvailable });
 
diff --git a/devtools/shared/commands/resource/tests/fission_document.html b/devtools/shared/commands/resource/tests/fission_document.html
index c2239faca62e..222f92d999eb 100644
--- a/devtools/shared/commands/resource/tests/fission_document.html
+++ b/devtools/shared/commands/resource/tests/fission_document.html
@@ -5,30 +5,6 @@
   <title>Test fission document</title>
   <!-- Any copyright is dedicated to the Public Domain.
      - http://creativecommons.org/publicdomain/zero/1.0/ -->
-  <script>
-  "use strict";
-
-  const params = new URLSearchParams(document.location.search);
-
-  // eslint-disable-next-line no-unused-vars
-  const worker = new Worker("https://example.com/browser/devtools/shared/commands/resource/tests/test_worker.js#simple-worker");
-
-  // eslint-disable-next-line no-unused-vars
-  const sharedWorker = new SharedWorker("https://example.com/browser/devtools/shared/commands/resource/tests/test_worker.js#shared-worker");
-
-  if (!params.has("noServiceWorker")) {
-    // Expose a reference to the registration so that tests can unregister it.
-    window.registrationPromise = navigator.serviceWorker.register("https://example.com/browser/devtools/shared/commands/resource/tests/test_service_worker.js#service-worker");
-  }
-
-  /* exported logMessageInWorker */
-  function logMessageInWorker(message) {
-    worker.postMessage({
-      type: "log-in-worker",
-      message,
-    });
-  }
-  </script>
 </head>
 <body>
 <p>Test fission iframe</p>
diff --git a/devtools/shared/commands/resource/tests/fission_document_workers.html b/devtools/shared/commands/resource/tests/fission_document_workers.html
new file mode 100644
index 000000000000..bbbe3e8bf8f9
--- /dev/null
+++ b/devtools/shared/commands/resource/tests/fission_document_workers.html
@@ -0,0 +1,47 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf8">
+  <title>Test fission document</title>
+  <!-- Any copyright is dedicated to the Public Domain.
+     - http://creativecommons.org/publicdomain/zero/1.0/ -->
+  <script>
+  "use strict";
+
+  const params = new URLSearchParams(document.location.search);
+
+  // eslint-disable-next-line no-unused-vars
+  const worker = new Worker("https://example.com/browser/devtools/shared/commands/resource/tests/test_worker.js#simple-worker");
+
+  // eslint-disable-next-line no-unused-vars
+  const sharedWorker = new SharedWorker("https://example.com/browser/devtools/shared/commands/resource/tests/test_worker.js#shared-worker");
+
+  if (!params.has("noServiceWorker")) {
+    // Expose a reference to the registration so that tests can unregister it.
+    window.registrationPromise = navigator.serviceWorker.register("https://example.com/browser/devtools/shared/commands/resource/tests/test_service_worker.js#service-worker");
+  }
+
+  /* exported logMessageInWorker */
+  function logMessageInWorker(message) {
+    worker.postMessage({
+      type: "log-in-worker",
+      message,
+    });
+  }
+  </script>
+</head>
+<body>
+<p>Test fission iframe</p>
+
+<script>
+  "use strict";
+  const iframe = document.createElement("iframe");
+  let iframeUrl = `https://example.org/browser/devtools/shared/commands/resource/tests/fission_iframe_workers.html`;
+  if (document.location.search) {
+    iframeUrl += `?${new URLSearchParams(document.location.search)}`;
+  }
+  iframe.src = iframeUrl;
+  document.body.append(iframe);
+</script>
+</body>
+</html>
diff --git a/devtools/shared/commands/resource/tests/fission_iframe.html b/devtools/shared/commands/resource/tests/fission_iframe.html
index deae49f83326..f67432110204 100644
--- a/devtools/shared/commands/resource/tests/fission_iframe.html
+++ b/devtools/shared/commands/resource/tests/fission_iframe.html
@@ -5,23 +5,6 @@
   <title>Test fission iframe document</title>
   <!-- Any copyright is dedicated to the Public Domain.
      - http://creativecommons.org/publicdomain/zero/1.0/ -->
-  <script>
-    "use strict";
-    const params = new URLSearchParams(document.location.search);
-    const hashSuffix = params.get("hashSuffix") || "in-iframe";
-    // eslint-disable-next-line no-unused-vars
-    const worker = new Worker("test_worker.js#simple-worker-" + hashSuffix);
-    // eslint-disable-next-line no-unused-vars
-    const sharedWorker = new SharedWorker("test_worker.js#shared-worker-" + hashSuffix);
-
-    /* exported logMessageInWorker */
-    function logMessageInWorker(message) {
-      worker.postMessage({
-        type: "log-in-worker",
-        message,
-      });
-    }
-  </script>
 </head>
 <body>
 <p>remote iframe</p>
diff --git a/devtools/shared/commands/resource/tests/fission_iframe_workers.html b/devtools/shared/commands/resource/tests/fission_iframe_workers.html
new file mode 100644
index 000000000000..deae49f83326
--- /dev/null
+++ b/devtools/shared/commands/resource/tests/fission_iframe_workers.html
@@ -0,0 +1,29 @@
+<!DOCTYPE HTML>
+<html>
+<head>
+  <meta charset="utf8">
+  <title>Test fission iframe document</title>
+  <!-- Any copyright is dedicated to the Public Domain.
+     - http://creativecommons.org/publicdomain/zero/1.0/ -->
+  <script>
+    "use strict";
+    const params = new URLSearchParams(document.location.search);
+    const hashSuffix = params.get("hashSuffix") || "in-iframe";
+    // eslint-disable-next-line no-unused-vars
+    const worker = new Worker("test_worker.js#simple-worker-" + hashSuffix);
+    // eslint-disable-next-line no-unused-vars
+    const sharedWorker = new SharedWorker("test_worker.js#shared-worker-" + hashSuffix);
+
+    /* exported logMessageInWorker */
+    function logMessageInWorker(message) {
+      worker.postMessage({
+        type: "log-in-worker",
+        message,
+      });
+    }
+  </script>
+</head>
+<body>
+<p>remote iframe</p>
+</body>
+</html>
diff --git a/devtools/shared/commands/target/tests/test_worker.js b/devtools/shared/commands/target/tests/test_worker.js
index 873041fcf071..3e6cd21f04d3 100644
--- a/devtools/shared/commands/target/tests/test_worker.js
+++ b/devtools/shared/commands/target/tests/test_worker.js
@@ -3,8 +3,6 @@
 
 "use strict";
 
-console.log("[WORKER] started", globalThis.location.toString(), globalThis);
-
 globalThis.onmessage = function(e) {
   const { type, message } = e.data;