diff --git a/tests/lib1/isystem.pc b/tests/lib1/isystem.pc
new file mode 100644
index 0000000..98416b5
--- /dev/null
+++ b/tests/lib1/isystem.pc
@@ -0,0 +1,4 @@
+Name: Bad
+Description: Demonstrates problems with -isystem in both old pkg-config and current pkgconf; see also https://bugs.freedesktop.org/show_bug.cgi?id=72584
+Version: 1
+Cflags: -isystem /opt/bad/include -isystem /opt/bad2/include
diff --git a/tests/run.sh.in b/tests/run.sh.in
index 820c3d1..f40b5d5 100644
--- a/tests/run.sh.in
+++ b/tests/run.sh.in
@@ -240,6 +240,10 @@ run_test "PKG_CONFIG_PATH='${selfdir}/lib1' ${1} --libs framework-2" \
 run_test "PKG_CONFIG_PATH='${selfdir}/lib1' ${1} --libs framework-1 framework-2" \
 	"-F/test/lib -framework framework-1 -framework framework-2"
 
+# test 87 - -isystem munging
+run_test "PKG_CONFIG_PATH='${selfdir}/lib1' ${1} --cflags isystem" \
+	"-isystem /opt/bad/include -isystem /opt/bad2/include"
+
 run_test "PKG_CONFIG_PATH='${selfdir}/lib1' ${1} --exists --print-errors 'foo > 0.6.0 foo < 0.8.0'; echo \$?" \
 	'1'