Computes the MD5 hash for a file.

The hash for a data file is used for looking up data files in a unique fashion. This is of particular use for tests; a test may require a particular version of a particular file, in which case it can be accessed via hash to get the appropriate version.

Typically, if you wish to write a test that requires a particular data file, you will want to submit that file to the astropy data servers, and use e.g. get_pkg_data_filename('hash/34c33b3eb0d56eb9462003af249eff28'), but with the hash for your file in place of the hash in the example.


The path to the file for which the hash should be generated.


The hex digest of the MD5 hash for the contents of the localfn file.