You're missing a dependency. If you're building fseqs.o, you need to add it as check_DEPENDENCIES
and also add it to your check_LDADD
line. If it was a library, you'd do the same thing, specifying the library file instead of all of the object files making the library up.
The check_DEPENDENCIES
bit ensures the correct rule is generated, and the check_LDADD
ensures the file is added to the command line while linking.