diff --git a/Makefile b/Makefile
index 739e95ab..8fbc78e2 100644
--- a/Makefile
+++ b/Makefile
@@ -497,7 +497,8 @@ LIBRARY_TESTS = lib/errors/errno_test.ww lib/ascii/ascii_test.ww \
 	  lib/hash/adler32/adler32_test.ww lib/hash/crc16/crc16_test.ww \
 	  lib/hash/crc32/crc32_test.ww lib/hash/crc64/crc64_test.ww \
 	  lib/path/path_test.ww lib/crypto/sha256/sha256_test.ww \
-	  lib/hash/siphash/siphash_test.ww
+	  lib/hash/siphash/siphash_test.ww \
+	  lib/os/os_test.ww lib/os/stat_test.ww lib/dirs/dirs_test.ww
 
 # These real sources have a standalone-compilation contract that is not
 # subsumed by a library @test import owner.