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Dimitrios Kechagias


Test2::Aggregate - Aggregate tests


    use Test2::Aggregate;

        dirs => \@test_dirs



Version 0.11


Aggregates all tests specified with dirs (which can even be individual tests) to avoid forking, reloading etc that can help with performance (dramatically if you have numerous small tests) and also facilitate group profiling. Test files are expected to end in .t and are run as subtests of a single aggregate test.

A bit similar, but simpler in concept and execution to Test::Aggregate, which makes it more likely to work with your test suite (especially if you use modern tools like Test2). It does not even try to package each test by default, which may be good or bad (e.g. redefines), depending on your requirements.

Generally, the way to use this module is to try to aggregate sets of quick tests (e.g. unit tests). Try to iterativelly add tests to the aggregator, dropping those that do not work.



    my $stats = Test2::Aggregate::run_tests(
        dirs          => \@dirs,              # optional if lists defined
        lists         => \@lists,             # optional if dirs defined
        excludes      => \@exclude_regexes,   # optional
        root          => '/testroot/',        # optional
        load_modules  => \@modules,           # optional
        package       => 0,                   # optional
        shuffle       => 0,                   # optional
        sort          => 0,                   # optional
        reverse       => 0,                   # optional
        unique        => 1,                   # optional
        repeat        => 1,                   # optional, requires Test2::Plugin::BailOnFail for < 0
        slow          => 0,                   # optional
        override      => \%override,          # optional, requires Sub::Override
        stats_output  => $stats_output_path,  # optional
        extend_stats  => 0,                   # optional
        test_warnings => 0                    # optional

Runs the aggregate tests. Returns a hashref with stats like this:

  $stats = {
    'test.t' => {
      'test_no'   => 1,                 # numbering starts at 1
      'pass_perc' => 100,               # for single runs pass/fail is 100/0
      'timestamp' => '20190705T145043', # start of test
      'time'      => '0.1732',          # seconds - only with stats_output
      'warnings'  => $STDERR            # only with test_warnings on non empty STDERR

The parameters to pass:

  • dirs (either this or lists is required)

    An arrayref containing directories which will be searched recursively, or even individual tests. The directories (unless shuffle or reverse are true) will be processed and tests run in order specified.

  • lists (either this or dirs is required)

    Arrayref of flat files from which each line will be pushed to dirs (so they have a lower precedence - note root still applies).

  • excludes (optional)

    Arrayref of strings with regex patterns to filter out tests that you want excluded.

  • root (optional)

    If defined, must be a valid root directory that will prefix all dirs and lists items. You may want to set it to './' if you want dirs relative to the current directory and the dot is not in your @INC.

  • load_modules (optional)

    Arrayref with modules to be loaded (with eval "use ...") at the start of the test. Useful for testing modules with special namespace requirements.

  • package (optional)

    Will package each test in its own namespace. While it will help avoid things like redefine warnings, it may break some tests when aggregating them, so it is disabled by default.

  • override (optional)

    Pass Sub::Override key/values as a hashref.

  • repeat (optional)

    Number of times to repeat the test(s) (default is 1 for a single run). If repeat is negative, the tests will repeat until they fail (or produce a warning if test_warnings is also set).

  • unique (optional)

    From v0.11, duplicate tests are by default removed from the running list as that could mess up the stats output. You can still define it as false to allow duplicate tests in the list.

  • shuffle (optional)

    Random order of tests if set to true. Will override sort.

  • sort (optional)

    Sort tests alphabetically if set to true. Provides a way to fix the test order across systems.

  • reverse (optional)

    Reverse order of tests if set to true.

  • slow (optional)

    When true, tests will be skipped if the environment variable SKIP_SLOW is set.

  • test_warnings (optional)

    Tests for warnings over all the tests if set to true - this is added as a final test which expects zero as the number of tests which had STDERR output. The STDERR output of each test will be printed at the end of the test run (and included in the test run result hash), so if you want to see warnings the moment they are generated (for debugging etc), then leave this option disabled.

  • stats_output_path (optional)

    stats_output_path specifies a path where a file will be created to print out running time per test (average if multiple iterations) and passing percentage. Output is sorted from slowest test to fastest. On negative repeat the stats of each successful run will be written separately instead of the averages. The name of the file is caller_script-YYYYMMDDTHHmmss.txt. If - is passed instead of a path, then the output will be written to STDOUT. The timing stats are useful because the test harness doesn't normally measure time per subtest (remember, your individual aggregated tests become subtests).

  • extend_stats (optional)

    This option is to make the default output of stats_output_path be fixed, but still allow additions in future versions that will only be written with the extend_stats option enabled. Additions with extend_stats as of current version:

      - starting date/time in ISO_8601.


Not all tests can be modified to run under the aggregator, it is not intended for tests that require an isolated environment, do overrides etc. For other tests which can potentially run under the aggregator, sometimes very simple changes may be needed like giving unique names to subs (or not warning for redefines, or trying the package option), replacing things that complain, restoring the environment at the end of the test etc.

Unit tests are usually great for aggregating. You could use the hash that run_tests returns in a script that tries to add more tests automatically to an aggregate list to see which added tests passed and keep them, dropping failures.

The environment variable AGGREGATE_TESTS will be set while the tests are running for your convenience. Example usage is making a test you know cannot run under the aggregator check and croak if it was run under it, or a module that can only be loaded once, so you load it on the aggregated test file and then use something like this in the individual test files:

 eval 'use My::Module' unless $ENV{AGGREGATE_TESTS};

Trying to aggregate too many tests into a single one can be counter-intuitive as you would ideally want to parallelize your test suite (so a super-long aggregated test continuing after the rest are done will slow down the suite). And in general more tests will run aggregated if they are grouped so that tests that can't be aggregated together are in different groups.

In general you can call Test2::Aggregate::run_tests multiple times in a test and even load run_tests with tests that already contain another run_tests, the only real issue with multiple calls is that if you use repeat < 0 on a call, Test2::Plugin::BailOnFail is loaded so any subsequent failure, on any following run_tests call will trigger a Bail.


Dimitrios Kechagias, <dkechag at cpan.org>


Please report any bugs or feature requests to bug-test2-aggregate at rt.cpan.org, or through the web interface at https://rt.cpan.org/NoAuth/ReportBug.html?Queue=Test2-Aggregate. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.




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