diff --git a/INSTALL b/INSTALL
index de60d10..d0465f0 100644
--- a/INSTALL
+++ b/INSTALL
@@ -46,6 +46,11 @@ error message starting with the word "FATAL". All other error
 messages visible in the log are a result of negative testing where
 the utility is expected to exit with an error.
 
+The files test/t1.tst, test/t2.tst and so on are individual test
+suites. It is possible to run a single test suite. For example to
+run test/t4.tst the following command can be used:
+make test TESTSUITE=4
+
 Custom Installation
 ===================
 The options to the config script are detailed below. Note that this
diff --git a/Makefile.in b/Makefile.in
index 0bd9fe1..23ecde1 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -266,7 +266,7 @@ $(PROG): $(OBJS)
 	$(LINK) -o $@ $(OBJS) $(LDLIBS)
 
 test: all
-	(cd test; ulimit -c unlimited; sh ./run_test.sh) 2>&1 | tee test.log
+	(cd test; ulimit -c unlimited; sh ./run_test.sh $(TESTSUITE) ) 2>&1 | tee test.log
 
 clean:
 	$(RM) $(PROG) $(OBJS) $(BAKFILES)