--- a/im/app/Makefile.in
+++ b/im/app/Makefile.in
@@ -337,16 +337,23 @@ module.ver: module.ver.in $(DEPTH)/confi
 _RC_STRING += -SRCDIR .
 module.rc: module.ver
 
 GARBAGE += module.ver
 
 libs:: $(srcdir)/profile/prefs.js
 	$(INSTALL) $(IFLAGS1) $^ $(DIST)/bin/defaults/profile
 
+# XXX This is a hack to ensure that we get the right xpcshell.ini for our tests.
+# mozilla-central does this in testing/xpcshell-tests which means that it is very
+# hard for anyone to specify anything else.
+libs::
+	$(INSTALL) $(topsrcdir)/instantbird/test/xpcshell.ini $(MOZDEPTH)/_tests/xpcshell
+	cp $(topsrcdir)/instantbird/test/xpcshell.ini $(MOZDEPTH)/_tests/xpcshell/all-test-dirs.list
+
 ifeq (cocoa,$(MOZ_WIDGET_TOOLKIT))
 
 AB := $(firstword $(subst -, ,$(AB_CD)))
 
 MAC_APP_NAME = $(MOZ_APP_DISPLAYNAME)
 
 ifdef MOZ_DEBUG
 MAC_APP_NAME := $(MAC_APP_NAME)Debug

--- a/im/build.mk
+++ b/im/build.mk
@@ -135,16 +135,19 @@ FORCE_UPDATE := components/components.li
 # SYMBOL_SERVER_HOST=symbols.instantbird.org
 # SYMBOL_SERVER_PATH=/www/instantbird/socorro/symbols
 # SYMBOL_SERVER_PORT=22
 # SYMBOL_SERVER_USER=buildbot
 
 distribution:
 	@$(MAKE) buildsymbols
 	@$(MAKE) -C instantbird/installer libs installer
+ifdef ENABLE_TESTS
+	$(MAKE) xpcshell-tests
+endif
 ifdef MOZ_UPDATE_PACKAGING
 	$(MAKE) -C $(MOZDEPTH)/tools/update-packaging full-update PKG_INST_PATH=
 endif
 ifdef L10NBASEDIR
 	$(foreach locale,$(SHIPPED_LOCALES),$(MAKE) -C instantbird/locales/ repack-$(locale) LOCALE_MERGEDIR=mergedir ;)
 endif
 ifdef MOZ_UPDATE_PACKAGING
 ifdef LIST_PREVIOUS_MAR_CMD

--- a/im/config/mozconfigs/linux/mozconfig
+++ b/im/config/mozconfigs/linux/mozconfig
@@ -12,15 +12,14 @@ mk_add_options MOZ_MAKE_FLAGS="-j4"
 mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/../obj-instantbird
 
 ac_add_options --with-ccache
 ac_add_options --enable-application=instantbird
 ac_add_options --enable-update-channel=nightly
 ac_add_options --enable-update-packaging
 ac_add_options --enable-optimize
 ac_add_options --disable-debug
-ac_add_options --disable-tests
 ac_add_options --disable-dbus
 ac_add_options --disable-necko-wifi
 
 if [ `date +%m%d` = 1031 -o `date +%m%d` = 1101 ]; then
 ac_add_options --with-branding=instantbird/branding/halloween
 fi

--- a/im/config/mozconfigs/linux/mozconfig-release
+++ b/im/config/mozconfigs/linux/mozconfig-release
@@ -12,13 +12,12 @@ mk_add_options MOZ_MAKE_FLAGS="-j4"
 mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/../obj-instantbird
 
 ac_add_options --with-ccache
 ac_add_options --enable-application=instantbird
 ac_add_options --enable-update-channel=release
 ac_add_options --enable-update-packaging
 ac_add_options --enable-optimize
 ac_add_options --disable-debug
-ac_add_options --disable-tests
 ac_add_options --disable-dbus
 ac_add_options --disable-necko-wifi
 ac_add_options --enable-official-branding
 ac_add_options --with-l10n-base=..

--- a/im/config/mozconfigs/macosx/mozconfig
+++ b/im/config/mozconfigs/macosx/mozconfig
@@ -27,13 +27,12 @@ ac_add_options --enable-debug-symbols="-
 mk_add_options MOZ_MAKE_FLAGS="-j4"
 mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/../obj-instantbird
 
 ac_add_options --enable-application=instantbird
 ac_add_options --enable-update-channel=nightly
 ac_add_options --enable-update-packaging
 ac_add_options --enable-optimize
 ac_add_options --disable-debug
-ac_add_options --disable-tests
 
 if [ `date +%m%d` = 1031 -o `date +%m%d` = 1101 ]; then
 ac_add_options --with-branding=instantbird/branding/halloween
 fi

--- a/im/config/mozconfigs/macosx/mozconfig-release
+++ b/im/config/mozconfigs/macosx/mozconfig-release
@@ -27,11 +27,10 @@ ac_add_options --enable-debug-symbols="-
 mk_add_options MOZ_MAKE_FLAGS="-j4"
 mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/../obj-instantbird
 
 ac_add_options --enable-application=instantbird
 ac_add_options --enable-update-channel=release
 ac_add_options --enable-update-packaging
 ac_add_options --enable-optimize
 ac_add_options --disable-debug
-ac_add_options --disable-tests
 ac_add_options --enable-official-branding
 ac_add_options --with-l10n-base=..

--- a/im/config/mozconfigs/win32/mozconfig
+++ b/im/config/mozconfigs/win32/mozconfig
@@ -11,16 +11,15 @@ export LDFLAGS="-LTCG"
 export MOZ_DEBUG_SYMBOLS=1
 
 mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/../obj-instantbird
 
 ac_add_options --enable-application=instantbird
 ac_add_options --enable-update-channel=nightly
 ac_add_options --enable-optimize
 ac_add_options --disable-debug
-ac_add_options --disable-tests
 ac_add_options --disable-webm
 ac_add_options --enable-update-packaging
 ac_add_options --enable-jemalloc
 
 if [ `date +%m%d` = 1031 -o `date +%m%d` = 1101 ]; then
 ac_add_options --with-branding=instantbird/branding/halloween
 fi

--- a/im/config/mozconfigs/win32/mozconfig-release
+++ b/im/config/mozconfigs/win32/mozconfig-release
@@ -11,14 +11,13 @@ export LDFLAGS="-LTCG"
 export MOZ_DEBUG_SYMBOLS=1
 
 mk_add_options MOZ_OBJDIR=@TOPSRCDIR@/../obj-instantbird
 
 ac_add_options --enable-application=instantbird
 ac_add_options --enable-update-channel=release
 ac_add_options --enable-optimize
 ac_add_options --disable-debug
-ac_add_options --disable-tests
 ac_add_options --disable-webm
 ac_add_options --enable-update-packaging
 ac_add_options --enable-jemalloc
 ac_add_options --enable-official-branding
 ac_add_options --with-l10n-base=..