diff --git a/mailnews/base/test/Makefile.in b/mailnews/base/test/Makefile.in
index 15813a188b..f1efe1201c 100644
--- a/mailnews/base/test/Makefile.in
+++ b/mailnews/base/test/Makefile.in
@@ -13,10 +13,6 @@ include $(DEPTH)/config/autoconf.mk
 
 include $(topsrcdir)/config/config.mk
 
-CPP_UNIT_TESTS = \
-    TestMailCookie.cpp \
-    $(NULL)
-
 include $(topsrcdir)/config/rules.mk
 
 LOCAL_INCLUDES = \
diff --git a/mailnews/base/test/moz.build b/mailnews/base/test/moz.build
index 8dc2ae73b6..fca1fa7994 100644
--- a/mailnews/base/test/moz.build
+++ b/mailnews/base/test/moz.build
@@ -5,3 +5,7 @@
 
 XPCSHELL_TESTS_MANIFESTS += ['unit/xpcshell.ini']
 
+CPP_UNIT_TESTS += [
+    'TestMailCookie.cpp',
+]
+