Add minimal tests.

Makefile

@@ -9,4 +9,7 @@ install-extra:
 	mkdir -p $(DESTDIR)/$(datarootdir)/aclocal
 	install -c -m644 pkg.m4 $(DESTDIR)/$(datarootdir)/aclocal/pkg.m4
 
+check: $(PROG)
+	$(SHELL) tests/run.sh ./$(PROG)
+
 include .deps

tests/lib1/foo.pc

@@ -0,0 +1,10 @@
+prefix=/usr
+exec_prefix=${prefix}
+libdir=${prefix}/lib
+includedir=${prefix}/include
+
+Name: foo
+Description: A testing pkg-config file
+Version: 1.2.3
+Libs: -L${libdir} -lfoo
+Cflags: -fPIC -I${includedir}/foo

tests/run.sh

@@ -0,0 +1,57 @@
+#!/bin/sh
+# Tests for pkg-config compliance.
+# * Copyright (c) 2012 Michał Górny <mgorny@gentoo.org>.
+
+done=0
+failed=0
+
+run_test() {
+	local res t_ret 2>/dev/null || true
+
+	echo "$ ${1}"
+	eval res="\$(${1})"
+	echo "${res}"
+
+	t_ret=0
+	while [ ${#} -gt 1 ]; do
+		shift
+
+		case "${res}" in
+			*${1}*)
+				;;
+			*)
+				echo "! expected ${1}"
+				t_ret=1
+				;;
+		esac
+	done
+
+	if [ ${t_ret} -eq 0 ]; then
+		echo "+ [OK]"
+	else
+		failed=$(( failed + 1 ))
+	fi
+	done=$(( done + 1 ))
+
+	echo
+}
+
+selfdir=$(cd "$(dirname "${0}")"; pwd)
+
+# 1) overall 'is it working?' test
+run_test "PKG_CONFIG_PATH=${selfdir}/lib1 ${1} --libs foo" \
+	'-lfoo'
+run_test "PKG_CONFIG_PATH=${selfdir}/lib1 ${1} --cflags --libs foo" \
+	'-lfoo' '-I/usr/include/foo' '-fPIC'
+run_test "PKG_CONFIG_PATH=${selfdir}/lib1 ${1} --exists 'foo > 1.2'; echo \$?" \
+	'0'
+run_test "PKG_CONFIG_PATH=${selfdir}/lib1 ${1} --exists 'foo > 1.2.3'; echo \$?" \
+	'1'
+
+if [ ${failed} -gt 0 ]; then
+	echo "${failed} of ${done} tests failed. See output for details." >&2
+	exit 1
+else
+	echo "${done} tests done. All succeeded." >&2
+	exit 0
+fi