diff --git a/docshell/test/unit/test_allowJavascript.js b/docshell/test/unit/test_allowJavascript.js
index c09e1108d78e..4b760c3e3b02 100644
--- a/docshell/test/unit/test_allowJavascript.js
+++ b/docshell/test/unit/test_allowJavascript.js
@@ -31,8 +31,12 @@ server.registerPathHandler("/", (request, response) => {
   response.write(HTML);
 });
 
+function getResourceURI(file) {
+  return Services.io.newFileURI(do_get_file(file)).spec;
+}
+
 const { AllowJavascriptParent } = ChromeUtils.import(
-  "resource://test/AllowJavascriptParent.jsm"
+  getResourceURI("AllowJavascriptParent.jsm")
 );
 
 async function assertScriptsAllowed(bc, expectAllowed, desc) {
@@ -65,11 +69,11 @@ add_task(async function() {
   ChromeUtils.registerWindowActor(ACTOR, {
     allFrames: true,
     child: {
-      moduleURI: "resource://test/AllowJavascriptChild.jsm",
+      moduleURI: getResourceURI("AllowJavascriptChild.jsm"),
       events: { load: { capture: true } },
     },
     parent: {
-      moduleURI: "resource://test/AllowJavascriptParent.jsm",
+      moduleURI: getResourceURI("AllowJavascriptParent.jsm"),
     },
   });
 
diff --git a/dom/indexedDB/test/unit/test_globalObjects_other.js b/dom/indexedDB/test/unit/test_globalObjects_other.js
index 3727384ae690..d4d60d8bad90 100644
--- a/dom/indexedDB/test/unit/test_globalObjects_other.js
+++ b/dom/indexedDB/test/unit/test_globalObjects_other.js
@@ -14,7 +14,7 @@ function* testSteps() {
 
   // Test for IDBKeyRange and indexedDB availability in JS modules.
   const { GlobalObjectsModule } = ChromeUtils.import(
-    "resource://test/GlobalObjectsModule.jsm"
+    getSpec("GlobalObjectsModule.jsm")
   );
   let test = new GlobalObjectsModule();
   test.ok = ok;
diff --git a/js/xpconnect/loader/mozJSComponentLoader.cpp b/js/xpconnect/loader/mozJSComponentLoader.cpp
index 104f260f1779..c3470970794d 100644
--- a/js/xpconnect/loader/mozJSComponentLoader.cpp
+++ b/js/xpconnect/loader/mozJSComponentLoader.cpp
@@ -1253,12 +1253,6 @@ nsresult mozJSComponentLoader::Import(JSContext* aCx,
     // Note: This implies EnsureURI().
     MOZ_TRY(info.EnsureResolvedURI());
 
-    // Reject imports from untrusted sources.
-    if ((!info.URI()->SchemeIs("resource")) &&
-        (!info.URI()->SchemeIs("chrome"))) {
-      return NS_ERROR_DOM_SECURITY_ERR;
-    }
-
     // get the JAR if there is one
     nsCOMPtr<nsIJARURI> jarURI;
     jarURI = do_QueryInterface(info.ResolvedURI(), &rv);
diff --git a/js/xpconnect/tests/unit/test_bug408412.js b/js/xpconnect/tests/unit/test_bug408412.js
index 06321a6f876b..e73c15cab8ad 100644
--- a/js/xpconnect/tests/unit/test_bug408412.js
+++ b/js/xpconnect/tests/unit/test_bug408412.js
@@ -3,8 +3,13 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
  
 function run_test() {
+  var file = do_get_file("syntax_error.jsm");
+  var ios = Cc["@mozilla.org/network/io-service;1"]
+              .getService(Ci.nsIIOService);
+  var uri = ios.newFileURI(file);
+
   try {
-    ChromeUtils.import("resource://test/syntax_error.jsm");
+    ChromeUtils.import(uri.spec);
     do_throw("Failed to report any error at all");
   } catch (e) {
     Assert.notEqual(/^SyntaxError:/.exec(e + ''), null);
diff --git a/js/xpconnect/tests/unit/test_import.js b/js/xpconnect/tests/unit/test_import.js
index 4aa72c72c6d3..9be6158fd11b 100644
--- a/js/xpconnect/tests/unit/test_import.js
+++ b/js/xpconnect/tests/unit/test_import.js
@@ -49,10 +49,8 @@ function run_test() {
   dump("resURI: " + resURI + "\n");
   var filePath = res.resolveURI(resURI);
   var scope3 = {};
-  Assert.throws(
-    () => ChromeUtils.import(filePath, scope3),
-    /SecurityError/, "Expecting file URI not to be imported"
-  );
+  Assert.throws(() => ChromeUtils.import(filePath, scope3),
+                /NS_ERROR_UNEXPECTED/);
 
   // make sure we throw when the second arg is bogus
   var didThrow = false;
@@ -90,12 +88,4 @@ function run_test() {
               .createInstance(Ci.nsIClassInfo);
   Assert.ok(Boolean(bar));
   Assert.ok(bar.contractID == contractID + "2");
-
-  // make sure we throw when the URL scheme is not known
-  var scope4 = {};
-  const wrongScheme = "data:text/javascript,var a = {a:1}";
-  Assert.throws(
-    () => ChromeUtils.import(wrongScheme, scope4),
-    /SecurityError/, "Expecting data URI not to be imported"
-  );
 }
diff --git a/toolkit/components/backgroundtasks/tests/BackgroundTask_crash.jsm b/toolkit/components/backgroundtasks/tests/BackgroundTask_crash.jsm
index fb64983e12f6..b3d7c25705c0 100644
--- a/toolkit/components/backgroundtasks/tests/BackgroundTask_crash.jsm
+++ b/toolkit/components/backgroundtasks/tests/BackgroundTask_crash.jsm
@@ -12,15 +12,9 @@ async function runBackgroundTask(commandLine) {
   // sibling `testcrasher` library to be in the current working
   // directory.  Fail right away if we can't find the module or the
   // native library.
-  let cwd = Services.dirsvc.get("CurWorkD", Ci.nsIFile);
-  let protocolHandler = Services.io
-    .getProtocolHandler("resource")
-    .QueryInterface(Ci.nsIResProtocolHandler);
-  var curDirURI = Services.io.newFileURI(cwd);
-  protocolHandler.setSubstitution("test", curDirURI);
-
+  let testPath = Services.dirsvc.get("CurWorkD", Ci.nsIFile).path;
   const { CrashTestUtils } = ChromeUtils.import(
-    "resource://test/CrashTestUtils.jsm"
+    `file://${testPath}/CrashTestUtils.jsm`
   );
 
   // Get the temp dir.
diff --git a/toolkit/components/extensions/moz.build b/toolkit/components/extensions/moz.build
index 8cc1fc1bec37..e2f408da316a 100755
--- a/toolkit/components/extensions/moz.build
+++ b/toolkit/components/extensions/moz.build
@@ -53,8 +53,6 @@ TESTING_JS_MODULES += [
     "ExtensionTestCommon.jsm",
     "ExtensionXPCShellUtils.jsm",
     "MessageChannel.jsm",
-    "test/xpcshell/data/TestWorkerWatcherChild.jsm",
-    "test/xpcshell/data/TestWorkerWatcherParent.jsm",
 ]
 
 DIRS += [
diff --git a/toolkit/components/extensions/test/xpcshell/head_service_worker.js b/toolkit/components/extensions/test/xpcshell/head_service_worker.js
index cefd26f6afda..a2c8cf326039 100644
--- a/toolkit/components/extensions/test/xpcshell/head_service_worker.js
+++ b/toolkit/components/extensions/test/xpcshell/head_service_worker.js
@@ -111,12 +111,15 @@ class TestWorkerWatcher extends ExtensionCommon.EventEmitter {
 
   registerProcessActor() {
     const { JS_ACTOR_NAME } = this;
+    const getModuleURI = fileName =>
+      Services.io.newFileURI(do_get_file(`${this.dataRelPath}/${fileName}`))
+        .spec;
     ChromeUtils.registerProcessActor(JS_ACTOR_NAME, {
       parent: {
-        moduleURI: `resource://testing-common/${JS_ACTOR_NAME}Parent.jsm`,
+        moduleURI: getModuleURI(`${JS_ACTOR_NAME}Parent.jsm`),
       },
       child: {
-        moduleURI: `resource://testing-common/${JS_ACTOR_NAME}Child.jsm`,
+        moduleURI: getModuleURI(`${JS_ACTOR_NAME}Child.jsm`),
       },
     });
   }