Language testing is an important element in the cycle of a programming language development. A part of these tests aim at determining features of a language such as what type of binders the language has, whether evaluation takes place underneath a binder, as well as other programming languages features.

In prior work, we have proposed languages-as-databases, an approach that is based on storing languages as databases, which then can be interrogated with declarative queries.

This paper illustrates a number of language tests on various aspects of programming languages. We also formulate tests that establish whether the language at hand conforms to the GSOS rule format, therefore deriving that bisimilarity is a congruence. Our tests show that languages-as-databases provides a lightweight approach to language testing.