diff --git a/etc/mtree/BSD.tests.dist b/etc/mtree/BSD.tests.dist
index b7ebbb9949a6..2d5d8a98cddd 100644
--- a/etc/mtree/BSD.tests.dist
+++ b/etc/mtree/BSD.tests.dist
@@ -49,8 +49,12 @@
         lib
             atf
                 libatf-c
+                    detail
+                    ..
                 ..
                 libatf-c++
+                    detail
+                    ..
                 ..
                 test-programs
                 ..
diff --git a/lib/atf/libatf-c++/tests/Makefile b/lib/atf/libatf-c++/tests/Makefile
index db10fce8dceb..1ab5fdaa6e4c 100644
--- a/lib/atf/libatf-c++/tests/Makefile
+++ b/lib/atf/libatf-c++/tests/Makefile
@@ -3,6 +3,7 @@
 .include <bsd.init.mk>
 
 TESTSDIR=	${TESTSBASE}/lib/atf/libatf-c++
+TESTS_SUBDIRS=	detail
 
 ATF=		${.CURDIR:H:H:H:H}/contrib/atf
 .PATH:		${ATF}/atf-c++
@@ -14,7 +15,6 @@ FILESDIR=	${TESTSDIR}
 FILES=		macros_hpp_test.cpp
 FILES+=		unused_test.cpp
 
-# Tests in atf-c++.
 .for _T in	atf_c++_test \
 		build_test \
 		check_test \
@@ -28,20 +28,4 @@ SRCS.${_T}=	${_T}.cpp test_helpers.cpp
 
 ATF_TESTS_SH=	pkg_config_test
 
-# Tests in atf-c++/detail.
-
-.for _T in	application_test \
-		env_test \
-		exceptions_test \
-		expand_test \
-		fs_test \
-		parser_test \
-		process_test \
-		sanity_test \
-		text_test \
-		ui_test
-ATF_TESTS_CXX+=	${_T}
-SRCS.${_T}=	${_T}.cpp test_helpers.cpp
-.endfor
-
 .include <atf.test.mk>
diff --git a/lib/atf/libatf-c++/tests/Makefile.inc b/lib/atf/libatf-c++/tests/Makefile.inc
new file mode 100644
index 000000000000..265f86d1ed55
--- /dev/null
+++ b/lib/atf/libatf-c++/tests/Makefile.inc
@@ -0,0 +1,3 @@
+# $FreeBSD$
+
+.include "../Makefile.inc"
diff --git a/lib/atf/libatf-c++/tests/detail/Makefile b/lib/atf/libatf-c++/tests/detail/Makefile
new file mode 100644
index 000000000000..e4ed1a5f2727
--- /dev/null
+++ b/lib/atf/libatf-c++/tests/detail/Makefile
@@ -0,0 +1,26 @@
+# $FreeBSD$
+
+.include <bsd.init.mk>
+
+TESTSDIR=	${TESTSBASE}/lib/atf/libatf-c++/detail
+
+ATF=		${.CURDIR:H:H:H:H:H}/contrib/atf
+.PATH:		${ATF}/atf-c++/detail
+
+CFLAGS+=	-I${ATF}
+
+.for _T in	application_test \
+		env_test \
+		exceptions_test \
+		expand_test \
+		fs_test \
+		parser_test \
+		process_test \
+		sanity_test \
+		text_test \
+		ui_test
+ATF_TESTS_CXX+=	${_T}
+SRCS.${_T}=	${_T}.cpp test_helpers.cpp
+.endfor
+
+.include <atf.test.mk>
diff --git a/lib/atf/libatf-c/tests/Makefile b/lib/atf/libatf-c/tests/Makefile
index a5c2836f677c..14b199f591bb 100644
--- a/lib/atf/libatf-c/tests/Makefile
+++ b/lib/atf/libatf-c/tests/Makefile
@@ -3,6 +3,7 @@
 .include <bsd.init.mk>
 
 TESTSDIR=	${TESTSBASE}/lib/atf/libatf-c
+TESTS_SUBDIRS=	detail
 
 ATF=		${.CURDIR:H:H:H:H}/contrib/atf
 .PATH:		${ATF}/atf-c
@@ -19,8 +20,6 @@ FILESDIR=	${TESTSDIR}
 FILES=		macros_h_test.c
 FILES+=		unused_test.c
 
-# Tests in atf-c.
-
 .for _T in	atf_c_test \
 		build_test \
 		check_test \
@@ -36,24 +35,4 @@ SRCS.${_T}=	${_T}.c test_helpers.c
 
 ATF_TESTS_SH=	pkg_config_test
 
-# Tests in atf-c/detail.
-
-.for _T in	dynstr_test \
-		env_test \
-		fs_test \
-		list_test \
-		map_test \
-		process_test \
-		sanity_test \
-		text_test \
-		user_test
-ATF_TESTS_C+=	${_T}
-SRCS.${_T}=	${_T}.c test_helpers.c
-.endfor
-
-PROGS+=		process_helpers
-SRCS.process_helpers=	process_helpers.c
-MAN.process_helpers=	# defined
-BINDIR.process_helpers=	${TESTSDIR}
-
 .include <atf.test.mk>
diff --git a/lib/atf/libatf-c/tests/Makefile.inc b/lib/atf/libatf-c/tests/Makefile.inc
new file mode 100644
index 000000000000..265f86d1ed55
--- /dev/null
+++ b/lib/atf/libatf-c/tests/Makefile.inc
@@ -0,0 +1,3 @@
+# $FreeBSD$
+
+.include "../Makefile.inc"
diff --git a/lib/atf/libatf-c/tests/detail/Makefile b/lib/atf/libatf-c/tests/detail/Makefile
new file mode 100644
index 000000000000..82bbf6f0d7cb
--- /dev/null
+++ b/lib/atf/libatf-c/tests/detail/Makefile
@@ -0,0 +1,30 @@
+# $FreeBSD$
+
+.include <bsd.init.mk>
+
+TESTSDIR=	${TESTSBASE}/lib/atf/libatf-c/detail
+
+ATF=		${.CURDIR:H:H:H:H:H}/contrib/atf
+.PATH:		${ATF}/atf-c/detail
+
+CFLAGS+=	-I${ATF}
+
+.for _T in	dynstr_test \
+		env_test \
+		fs_test \
+		list_test \
+		map_test \
+		process_test \
+		sanity_test \
+		text_test \
+		user_test
+ATF_TESTS_C+=	${_T}
+SRCS.${_T}=	${_T}.c test_helpers.c
+.endfor
+
+PROGS+=		process_helpers
+SRCS.process_helpers=	process_helpers.c
+MAN.process_helpers=	# defined
+BINDIR.process_helpers=	${TESTSDIR}
+
+.include <atf.test.mk>
diff --git a/tools/build/mk/OptionalObsoleteFiles.inc b/tools/build/mk/OptionalObsoleteFiles.inc
index 0b886b42f96b..eb23eddafa26 100644
--- a/tools/build/mk/OptionalObsoleteFiles.inc
+++ b/tools/build/mk/OptionalObsoleteFiles.inc
@@ -4066,6 +4066,26 @@ OLD_FILES+=usr/share/man/man8/telnetd.8.gz
 .if ${MK_TESTS} == yes
 OLD_FILES+=usr/tests/lib/atf/libatf-c/test_helpers_test
 OLD_FILES+=usr/tests/lib/atf/test-programs/fork_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c++/application_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c++/env_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c++/exceptions_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c++/expand_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c++/fs_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c++/parser_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c++/process_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c++/sanity_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c++/text_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c++/ui_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c/dynstr_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c/env_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c/fs_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c/list_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c/map_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c/process_helpers
+OLD_FILES+=usr/tests/lib/atf/libatf-c/process_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c/sanity_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c/text_test
+OLD_FILES+=usr/tests/lib/atf/libatf-c/user_test
 .else
 # ATF libraries.
 OLD_FILES+=usr/bin/atf-sh