--- a/testing/testsuite-targets.mk
+++ b/testing/testsuite-targets.mk
@@ -3,19 +3,21 @@
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
 
 # Shortcut for mochitest* and xpcshell-tests targets,
 # replaces 'EXTRA_TEST_ARGS=--test-path=...'.
 ifdef TEST_PATH
 TEST_PATH_ARG := --test-path="$(TEST_PATH)"
 PEPTEST_PATH_ARG := --test-path="$(TEST_PATH)"
+IPCPLUGINS_PATH_ARG := --test-path="$(TEST_PATH)"
 else
 TEST_PATH_ARG :=
 PEPTEST_PATH_ARG := --test-path=_tests/peptest/tests/firefox/firefox_all.ini
+IPCPLUGINS_PATH_ARG := --test-path=dom/plugins/test
 endif
 
 # include automation-build.mk to get the path to the binary
 TARGET_DEPTH = $(DEPTH)
 include $(topsrcdir)/build/binary-location.mk
 
 SYMBOLS_PATH := --symbols-path=$(DIST)/crashreporter-symbols
 
@@ -134,23 +136,23 @@ mochitest-chrome:
 
 mochitest-a11y:
 	$(RUN_MOCHITEST) --a11y
 	$(CHECK_TEST_ERROR)
 
 mochitest-ipcplugins:
 ifeq (Darwin,$(OS_ARCH))
 ifeq (i386,$(TARGET_CPU))
-	$(RUN_MOCHITEST) --setpref=dom.ipc.plugins.enabled.i386.test.plugin=false --test-path=dom/plugins/test
+	$(RUN_MOCHITEST) --setpref=dom.ipc.plugins.enabled.i386.test.plugin=false $(IPCPLUGINS_PATH_ARG)
 endif
 ifeq (x86_64,$(TARGET_CPU))
-	$(RUN_MOCHITEST) --setpref=dom.ipc.plugins.enabled.x86_64.test.plugin=false --test-path=dom/plugins/test
+	$(RUN_MOCHITEST) --setpref=dom.ipc.plugins.enabled.x86_64.test.plugin=false $(IPCPLUGINS_PATH_ARG)
 endif
 ifeq (powerpc,$(TARGET_CPU))
-	$(RUN_MOCHITEST) --setpref=dom.ipc.plugins.enabled.ppc.test.plugin=false --test-path=dom/plugins/test
+	$(RUN_MOCHITEST) --setpref=dom.ipc.plugins.enabled.ppc.test.plugin=false $(IPCPLUGINS_PATH_ARG)
 endif
 else
 	$(RUN_MOCHITEST) --setpref=dom.ipc.plugins.enabled=false --test-path=dom/plugins/test
 endif
 	$(CHECK_TEST_ERROR)
 
 ifeq ($(OS_ARCH),Darwin)
 webapprt_stub_path = $(TARGET_DIST)/$(MOZ_MACBUNDLE_NAME)/Contents/MacOS/webapprt-stub$(BIN_SUFFIX)