diff --git a/configure/RULES_BUILD b/configure/RULES_BUILD
index 7d955798e..906d80c75 100644
--- a/configure/RULES_BUILD
+++ b/configure/RULES_BUILD
@@ -315,6 +315,13 @@ $(OBJLIB_MUNCHNAME):%.munch : %_ctdt$(OBJ) %$(OBJ)
 runtests: $(TESTSCRIPTS_$(BUILD_CLASS))
 	-$(PERL) -MTest::Harness -e 'runtests @ARGV if @ARGV;' $^
 
+testspec: $(TESTSCRIPTS_$(BUILD_CLASS))
+	@$(RM) $@
+	@echo OS-class: $(OS_CLASS) > $@
+	@echo Target-arch: $(T_A) >> $@
+	@echo Tests: $^ >> $@
+	$(if $(TESTSPEC_$(OS_CLASS)), @echo "Harness: $(TESTSPEC_$(OS_CLASS))" >> $@)
+
 # If there's a perl test script (.plt) available, use it
 %.t: ../%.plt
 	@$(RM) $@
diff --git a/src/libCom/test/Makefile b/src/libCom/test/Makefile
index edf4ab369..bbc888590 100644
--- a/src/libCom/test/Makefile
+++ b/src/libCom/test/Makefile
@@ -142,11 +142,12 @@ testHarness_SRCS += epicsRunLibComTests.c
 PROD_vxWorks = vxTestHarness
 vxTestHarness_SRCS += $(testHarness_SRCS)
 vxTestHarness_OBJS += $(INSTALL_BIN)/vxComLibrary
+TESTSPEC_vxWorks = vxTestHarness.munch; epicsRunLibComTests
 
 PROD_RTEMS += rtemsTestHarness
 rtemsTestHarness_SRCS += rtemsTestHarness.c
 rtemsTestHarness_SRCS += $(testHarness_SRCS)
-
+TESTSPEC_RTEMS = rtemsTestHarness.boot; epicsRunLibComTests
 
 TESTSCRIPTS_HOST += $(TESTS:%=%.t)