The write-test-dbs script will create a small set of test databases with a variety of data and record sizes (24, 28, & 32 bit).
These test databases are useful for testing code that reads MaxMind DB files.
There is also a
maps-with-pointers.raw file. This contains the raw output of
the MaxMind::DB::Writer::Serializer module, when given a series of maps which
share some keys and values. It is used to test that decoder code can handle
pointers to map keys and values, as well as to the whole map.
There are several ways to figure out what IP addresses are actually in the test databases. You can take a look at the source-data directory in this repository. This directory contains JSON files which are used to generate many (but not all) of the database files.
Some databases are intentionally broken and cannot be dumped. You can look at the script which generates these databases to see what IP addresses they include, which will be necessary for those databases which cannot be dumped because they contain intentional errors.