diff --git a/share/mk/bsd.opts.mk b/share/mk/bsd.opts.mk
--- a/share/mk/bsd.opts.mk
+++ b/share/mk/bsd.opts.mk
@@ -79,6 +79,7 @@
     CTF \
     INSTALL_AS_USER \
     RETPOLINE \
+    RUN_TESTS \
     STALE_STAGED \
     UBSAN \
     UNDEFINED_VERSION \
diff --git a/share/mk/bsd.test.mk b/share/mk/bsd.test.mk
--- a/share/mk/bsd.test.mk
+++ b/share/mk/bsd.test.mk
@@ -91,6 +91,11 @@
 .include <suite.test.mk>
 .endif
 
+.if ${MK_DIRDEPS_BUILD} == "yes" && ${MK_RUN_TESTS} == "yes"
+# Run tests as part of the build
+.include <host.test.mk>
+.endif
+
 .if !target(realcheck)
 realcheck: .PHONY
 	@echo "$@ not defined; skipping"
diff --git a/share/mk/host.test.mk b/share/mk/host.test.mk
new file mode 100644
--- /dev/null
+++ b/share/mk/host.test.mk
@@ -0,0 +1,65 @@
+#
+# For DIRDEPS_BUILD we may want to run tests for "host"
+# during the build - and fail the build if any test fails.
+#
+.if !target(__<bsd.test.mk>__)
+.error ${.PARSEFILE} cannot be included directly.
+.endif
+
+.if ${.MAKE.LEVEL} > 0 && !empty(_TESTS) && ${MACHINE:Nhost*} == ""
+
+# allow for customization
+.-include <local.host.test.mk>
+
+KYUA?= kyua
+
+# we need to make sure kyua-report can find the results
+KYUA_RESULTS?= ${.OBJDIR}/kyua.results
+KYUA_ARGS?= --results-file=${KYUA_RESULTS}
+KYUA_ENV?= HOME=${KYUA_HOME} TMPDIR=${.OBJDIR}
+KYUA_FLAGS?= --config none --loglevel=${KYUA_LOGLEVEL:Uinfo}
+KYUA_HOME?= ${OBJTOP}
+
+.if make(debug*)
+KYUA_LOGLEVEL?= debug
+.endif
+
+# some tests have files they need
+.if ${${PACKAGE}FILES:U:NKyuafile} != ""
+run-tests run-tests.log: link-test-files
+link-test-files: ${${PACKAGE}FILES:NKyuafile}
+	@for f in ${.ALLSRC:N*Kyuafile:M*/*}; do \
+	    ln -sf $$f .; \
+	done
+.endif
+
+# we do not want to stage any of this
+RUN_TESTS_LOG= run-tests.log
+MK_STAGING= no
+META_XTRAS+= ${RUN_TESTS_LOG}
+
+all run-tests: ${RUN_TESTS_LOG}
+
+# This is the main event.
+# Run kyua-test followed by kyua-report.
+# If we have any test failues we want to run kyua-report --verbose
+# Also on fail, we rename run-tests.log to run-tests.err so we save the
+# output but the target will be out-of-date.
+# We prepend ${.OBJDIR}:${.OBJDIR:H}: to PATH seen by kyua
+# so tests for things like cat, cp, cmp etc can find the one we just built
+# rather than the one from the host.
+${RUN_TESTS_LOG}: ${_TESTS} Kyuafile
+	@( export PATH=${.OBJDIR}:${.OBJDIR:H}:${PATH}; \
+	rm -f ${KYUA_RESULTS}; \
+	${KYUA_ENV} ${KYUA} ${KYUA_FLAGS} test ${KYUA_ARGS} -k ${.OBJDIR}/Kyuafile --build-root=${.OBJDIR} && \
+	${KYUA_ENV} ${KYUA} ${KYUA_FLAGS} report ${KYUA_ARGS} ) > ${.TARGET} || \
+	{ mv ${.TARGET} ${.TARGET:R}.err; \
+	${KYUA_ENV} ${KYUA} ${KYUA_FLAGS} report ${KYUA_ARGS} --verbose --results-filter broken,failed; echo See ${.TARGET:R:tA}.err; \
+	exit 1; }
+
+# make kyua-debug KYUA_DEBUG_ARGS=app:test
+kyua-debug:
+	@(export PATH=${.OBJDIR}:${.OBJDIR:H}:${PATH}; \
+	${KYUA_ENV} ${KYUA} ${KYUA_FLAGS} debug ${KYUA_DEBUG_ARGS}) || true
+
+.endif
diff --git a/share/mk/local.dirdeps.mk b/share/mk/local.dirdeps.mk
--- a/share/mk/local.dirdeps.mk
+++ b/share/mk/local.dirdeps.mk
@@ -250,3 +250,59 @@
 KERNEL_NAME:= ${KERNEL_NAME.${DEP_MACHINE}}
 
 .-include <site.dirdeps.mk>
+
+.if ${MK_RUN_TESTS} == "yes"
+# some the tests below will not run correctly on the host
+# as they require support files not present in .CURDIR
+BROKEN_HOST_TESTS += \
+	${BROKEN_HOST_DEP_TESTS} \
+	bin/cp/tests \
+	lib/atf/libatf-c++/tests \
+	lib/atf/libatf-c/tests \
+	lib/libarchive/tests \
+	lib/libnv/tests \
+	libexec/rtld-elf/tests \
+	sbin/devd/tests \
+	usr.bin/comm/tests \
+	usr.bin/du/tests \
+	usr.bin/procstat/tests \
+	usr.bin/sed/tests \
+	usr.bin/tar/tests \
+	usr.bin/tr/tests \
+	usr.bin/xargs/tests \
+	usr.bin/yacc/tests \
+	usr.sbin/makefs/tests \
+	usr.sbin/rpcbind/tests \
+
+# these all have broken dependencies which we choose not to fix for host
+BROKEN_HOST_DEP_TESTS += \
+	lib/msun/tests \
+	usr.bin/cut/tests \
+	usr.bin/diff/tests \
+	usr.bin/grep/tests \
+	usr.bin/gzip/tests \
+	usr.bin/printf/tests \
+
+.endif
+
+TESTS_DIR_LIST += tests
+# most of the tree only has Makefile.depend
+# by default we only want to run host tests for Makefile.depend.host
+TESTS_DEPENDFILE_PREFERENCE ?= Makefile.depend.host
+EXCLUDE_TESTS_FILTER += . \
+	lib/libcasper/services/cap_* \
+
+.for t in ${TESTS_DIR_LIST:O:u}
+.if !target(${DEP_RELDIR}/$t.test)
+.if ${BROKEN_HOST_TESTS:U:M${DEP_RELDIR}/$t} == "" && \
+	${RUN_TESTS_FILTER:U*:@m@${DEP_RELDIR:M$m}@} != "" && \
+	${DEP_RELDIR:${EXCLUDE_TESTS_FILTER:Uno:${M_ListToSkip}}} != "" && \
+	${TESTS_DEPENDFILE_PREFERENCE:@m@${exists(${SRCTOP}/${DEP_RELDIR}/$t/$m):?$m:}@} != ""
+# build but not via DIRDEPS to avoid circular dependencies
+_build_xtra_dirs += ${SRCTOP}/${DEP_RELDIR}/$t.host
+# mark it done
+${DEP_RELDIR}/$t.test:
+.endif
+.endif
+.endfor
+.endif