tests: Add lib/timestamp-test test case

Signed-off-by: Jakub Czapiga <jacz@semihalf.com>
Change-Id: I39abfc644fef085cef2175086a0e45a040b244de
Reviewed-on: https://review.coreboot.org/c/coreboot/+/46968
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Paul Fagerburg <pfagerburg@chromium.org>
diff --git a/tests/lib/Makefile.inc b/tests/lib/Makefile.inc
index 3062bca..27773b7 100644
--- a/tests/lib/Makefile.inc
+++ b/tests/lib/Makefile.inc
@@ -4,6 +4,7 @@
 tests-y += b64_decode-test
 tests-y += hexstrtobin-test
 tests-y += imd-test
+tests-y += timestamp-test
 
 string-test-srcs += tests/lib/string-test.c
 string-test-srcs += src/lib/string.c
@@ -17,4 +18,9 @@
 
 imd-test-srcs += tests/lib/imd-test.c
 imd-test-srcs += tests/stubs/console.c
-imd-test-srcs += src/lib/imd.c
\ No newline at end of file
+imd-test-srcs += src/lib/imd.c
+
+timestamp-test-srcs += tests/lib/timestamp-test.c
+timestamp-test-srcs += tests/stubs/timestamp.c
+timestamp-test-srcs += tests/stubs/console.c
+timestamp-test-stage := romstage