Writing tests for modules using database handles

astaines has asked for the wisdom of the Perl Monks concerning the following question:

Hi,

I am writing a module which wraps the table_info() function in DBI. Clearly it need a working database handle to operate on. I want to write some test scripts for it. These work fine on my system, where I can feed them a working databse handle easily.

How should I provide tests for other people to use, assuming that anyone else is ever mad enough to use this module? I may be missing something fundamental here, but all advice is gratefully accepted.

(Any comments on the basic idea of this module, and whether there's a better solution also welcome)

Anthony Staines

^^^^^^^^^^^^^^^

SYNOPSIS
      use DBIx::Information;
      my $dbinf->new($dbh);
  
      # Get a list of tables in the database
      my @tables = @{ $dbinf->tables()};
  
      # Get a list of variables in the whole database
      my @variables = @{ $dbinf->variables()};

      # Get a list of the variable in the table called $table_name;
      my @myvariable = @{ $dbinf->variable($table_name)};

      # Get two useful hashes-
      #     List keyed by table to anonymous arrays of the names of th
+e variables in each table
      #     Index keyed by variable name to anonymous arrays of the na
+mes of the table
      #     (or tables) in which each variable occurs.
      #
      my %list  = %{$dbinf->list()};
      my %index = %{$dbinf->index()};

      #Does the variable exist in the specified table
      my $exists = $dbinf->IsVarinTable($variable_name,$table_name);

DESCRIPTION
    This module provides a convenient interface to the contents of a s
+ingle
    database, or (possibly) a singe schema. I only have Mysql, and it 
+*will*
    work with this. If you have other databases fell free to test...

  EXPORT

    Nothing. don't even try.

AUTHOR
    Anthony.Staines@ucd.ie

SEE ALSO
    the perl manpage.
[download]

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Re: Writing tests for modules using database handles by chromatic (Archbishop) on Aug 02, 2001 at 04:48 UTC
DBD::CSV. DBD::RAM. Make it possible to set up your program with a different database handle. In your test program, open a handle to a file or memory database with just enough test data to make things work. I used DBD::CSV in a project, stuffed the applicable data after `__DATA__`, and wrote a small sub to dump things to a CSV file. Very simple: `sub make_db { open(OUT, '>page_data') or die "Can't open output db: $!"; while (<DATA>) { chomp; print OUT $_, "\015\012"; } close OUT; }` [download] Depending on how tricky your SQL calls are, you may have to get more tricky here. Hmm, it would be good to have someone write a DBI testing module. Any takers?	[reply] [d/l] [select]
Re: Writing tests for modules using database handles by bikeNomad (Priest) on Aug 02, 2001 at 04:45 UTC
Your test script could require a database handle to be set in a config file (and, of course, print a message if it isn't). The handle could be passed to the Makefile, as well. Look at the way that the various DBD modules do their testing. Isn't there a test database in the standard MySQL installation? That could be your default. The Device::SerialPort module does tests on a live serial port; if opening it fails, it prints out a message about how to change the configuration by editing a file.	[reply]