diff --git a/Makefile.in b/Makefile.in
index d00c6b4b52..170d79b8e1 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -10,6 +10,7 @@
 srcdir =	@srcdir@
 VPATH =		@srcdir@
 top_srcdir =	@top_srcdir@
+top_builddir =  @top_builddir@
 
 VERSION=@BIND9_VERSION@
 
@@ -89,7 +90,8 @@ force-test: test-force
 test-force:
 	status=0; \
 	(cd bin/tests && ${MAKE} ${MAKEDEFS} test) || status=1; \
-	(test -f unit/unittest.sh && $(SHELL) unit/unittest.sh) || status=1; \
+	(test -f ${top_builddir}/unit/unittest.sh && \
+		$(SHELL) ${top_builddir}/unit/unittest.sh) || status=1; \
 	exit $$status
 
 README: README.md
@@ -105,6 +107,6 @@ OPTIONS: OPTIONS.md
 		${W3M} -dump -cols 75 -O ascii -T text/html > $@
 
 unit::
-	sh ${top_srcdir}/unit/unittest.sh
+	sh ${top_builddir}/unit/unittest.sh
 
 clean::
diff --git a/lib/dns/tests/Makefile.in b/lib/dns/tests/Makefile.in
index ade4912fa3..955c0b2418 100644
--- a/lib/dns/tests/Makefile.in
+++ b/lib/dns/tests/Makefile.in
@@ -242,7 +242,7 @@ dstrandom_test@EXEEXT@: dstrandom_test.@O@ ${ISCDEPLIBS} ${DNSDEPLIBS}
 			${ISCLIBS} ${ISCPK11LIBS} ${LIBS}
 
 unit::
-	sh ${top_srcdir}/unit/unittest.sh
+	sh ${top_builddir}/unit/unittest.sh
 
 clean distclean::
 	rm -f ${TARGETS}
diff --git a/lib/irs/tests/Makefile.in b/lib/irs/tests/Makefile.in
index 788c30d1fd..f1bd3c01c4 100644
--- a/lib/irs/tests/Makefile.in
+++ b/lib/irs/tests/Makefile.in
@@ -46,7 +46,7 @@ resconf_test@EXEEXT@: resconf_test.@O@ ${CFGDEPLIBS} ${DNSDEPLIBS} ${IRSDEPLIBS}
 			resconf_test.@O@ ${LIBS}
 
 unit::
-	sh ${top_srcdir}/unit/unittest.sh
+	sh ${top_builddir}/unit/unittest.sh
 
 clean distclean::
 	rm -f ${TARGETS}
diff --git a/lib/isc/tests/Makefile.in b/lib/isc/tests/Makefile.in
index bd8626e7ed..f9cb409388 100644
--- a/lib/isc/tests/Makefile.in
+++ b/lib/isc/tests/Makefile.in
@@ -162,7 +162,7 @@ time_test@EXEEXT@: time_test.@O@ ${ISCDEPLIBS}
 			time_test.@O@ ${ISCLIBS} ${LIBS}
 
 unit::
-	sh ${top_srcdir}/unit/unittest.sh
+	sh ${top_builddir}/unit/unittest.sh
 
 clean distclean::
 	rm -f ${TARGETS}
diff --git a/lib/isccfg/tests/Makefile.in b/lib/isccfg/tests/Makefile.in
index fbe3eca3d6..f1ef64386e 100644
--- a/lib/isccfg/tests/Makefile.in
+++ b/lib/isccfg/tests/Makefile.in
@@ -47,7 +47,7 @@ parser_test@EXEEXT@: parser_test.@O@ ${ISCDEPLIBS} ${DNSDEPLIBS} ${ISCCFGDEPLIBS
 		        ${ISCLIBS} ${LIBS}
 
 unit::
-	sh ${top_srcdir}/unit/unittest.sh
+	sh ${top_builddir}/unit/unittest.sh
 
 clean distclean::
 	rm -f ${TARGETS}
diff --git a/lib/ns/tests/Makefile.in b/lib/ns/tests/Makefile.in
index afdc762119..7da7f8c54e 100644
--- a/lib/ns/tests/Makefile.in
+++ b/lib/ns/tests/Makefile.in
@@ -61,7 +61,7 @@ query_test@EXEEXT@: query_test.@O@ nstest.@O@ ${NSDEPLIBS} ${ISCDEPLIBS} ${DNSDE
 				${ISCLIBS} ${LIBS}
 
 unit::
-	sh ${top_srcdir}/unit/unittest.sh
+	sh ${top_builddir}/unit/unittest.sh
 
 clean distclean::
 	rm -f ${TARGETS}