--- a/python/mozbuild/mozbuild/action/test_archive.py
+++ b/python/mozbuild/mozbuild/action/test_archive.py
@@ -357,17 +357,29 @@ ARCHIVE_FILES = {
             'base': '',
             'pattern': 'mochitest/**',
         },
         {
             'source': buildconfig.topobjdir,
             'base': '',
             'pattern': 'mozinfo.json',
             'dest': 'mochitest'
-        }
+        },
+        {
+            'source': buildconfig.topobjdir,
+            'base': 'dist/xpi-stage',
+            'pattern': 'mochijar/**',
+            'dest': 'mochitest'
+        },
+        {
+            'source': buildconfig.topobjdir,
+            'base': 'dist/xpi-stage',
+            'pattern': 'specialpowers/**',
+            'dest': 'mochitest/extensions'
+        },
     ],
     'mozharness': [
         {
             'source': buildconfig.topsrcdir,
             'base': 'testing',
             'pattern': 'mozharness/**',
         },
     ],

deleted file mode 100644
--- a/testing/mochitest/Makefile.in
+++ /dev/null
@@ -1,15 +0,0 @@
-#
-# This Source Code Form is subject to the terms of the Mozilla Public
-# License, v. 2.0. If a copy of the MPL was not distributed with this
-# file, You can obtain one at http://mozilla.org/MPL/2.0/.
-
-
-_DEST_DIR = $(DEPTH)/_tests/$(relativesrcdir)
-
-include $(topsrcdir)/config/rules.mk
-
-libs:: 
-	(cd $(DIST)/xpi-stage && tar $(TAR_CREATE_FLAGS) - mochijar) | (cd $(_DEST_DIR) && tar -xf -)
-
-$(_DEST_DIR):
-	$(NSINSTALL) -D $@

--- a/testing/specialpowers/Makefile.in
+++ b/testing/specialpowers/Makefile.in
@@ -9,12 +9,10 @@ XPI_PKGNAME = specialpowers@mozilla.org
 include $(topsrcdir)/config/rules.mk
 
 libs-preqs = \
   $(call mkdir_deps,$(TEST_EXTENSIONS_DIR)) \
   $(NULL)
 
 libs:: $(libs-preqs)
 	(cd $(DIST)/xpi-stage && tar $(TAR_CREATE_FLAGS) - $(XPI_NAME)) | (cd $(TEST_EXTENSIONS_DIR) && tar -xf -)
-	$(NSINSTALL) -D $(DEPTH)/_tests/testing/mochitest/extensions/specialpowers
-	cp -RL $(DEPTH)/testing/specialpowers/specialpowers $(DEPTH)/_tests/testing/mochitest/extensions
 	$(NSINSTALL) -D $(DEPTH)/_tests/reftest/specialpowers
 	cp -RL $(DEPTH)/testing/specialpowers/specialpowers $(DEPTH)/_tests/reftest