setup a bit of a test framework

sh/Makefile

@@ -18,3 +18,6 @@ _installafter:
 	@# Put functions.sh into the init.d dir so 3rd party apps don't have to
 	@# be multilib aware
 	ln -snf ${PREFIX}/${RC_LIB}/sh/functions.sh ${DESTDIR}/${PREFIX}/${INITDIR} || exit $$?
+
+check test::
+	./runtests.sh

sh/runtests.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+
+top_srcdir=${top_srcdir:-..}
+. ${top_srcdir}/test/setup_env.sh
+
+ret=0
+
+tret=0
+ebegin "Testing yesno()"
+for f in yes YES Yes true TRUE True 1 ; do
+	if ! yesno ${f} ; then
+		((tret+=1))
+		echo "!${f}!"
+	fi
+done
+for f in no NO No false FALSE False 0 ; do
+	if yesno ${f} ; then
+		((tret+=1))
+		echo "!${f}!"
+	fi
+done
+eend ${tret}
+((ret+=tret))
+
+exit ${ret}