The corpus of tests at https://github.com/mongodb/mongo-c-driver/tree/master/src/libbson/tests/json/bson_corpus contains BSON inputs as well as Extended JSON equivalents meant for testing.

We should integrate those inputs into our tests and use them to test $serializeEJSON/$deserializeEJSON, as well as $convert format conversions.

These test inputs could also be used to test non-Query parsers and serialisers in the Server, such as the BSONObj::jsonString method.