"Metrics::Any::Adapter::Test" - a metrics reporting adapter for unit testing

       Paul Evans <leonerd@leonerd.org.uk>

perl v5.36.0                                       2023-09-29                   Metrics::Any::Adapter::Test(3pm)

       This Metrics::Any adapter type stores reported metrics locally, allowing access to them by the "metrics"
       method. This is useful to use in a unit test to check that the code under test reports the correct
       metrics.

       This adapter supports timer metrics by storing as distributions. By default, distributions store only a
       summary, giving the count and total duration. If required, the full values can be stored by setting
       "use_full_distributions".

       For predictable output of timer metrics in unit tests, a unit test may wish to use the
       "override_timer_duration" method.

       This adapter type supports batch mode reporting. Callbacks are invoked at the beginning of the "metrics"
       method.

metrics
          $result = Metrics::Any::Adapter::Test->metrics

       This class method returns a string describing all of the stored metric values.  Each is reported on a
       line formatted as

          name = value

       Each line, including the final one, is terminated by a linefeed. The metrics are sorted alphabetically.
       Any multi-part metric names will be joined with underscores ("_").

       Metrics that have additional labels are formatted with additional label names and label values in
       declared order after the name and before the "=" symbol:

          name l1:v1 l2:v2 = value

   use_full_distributions
          Metrics::Any::Adapter::Test->use_full_distributions;  # enables the option

          Metrics::Any::Adapter::Test->use_full_distributions( $enable );

       Sinceversion0.08.

       If enabled, this option stores the full value of every reported observation into distributions, rathr
       than just the count-and-total summary.

       Full value distributions will be formatted as a sequence of lines containing the count of observations at
       that particular value, in square brackets, followed by the summary count.

          name[v1] = c1
          name[v2] = c2
          ...
          name_count = c

       In order not to be too sensitive to numerical rounding errors, values are stored to only 3 decimal
       places.

   clear
          Metrics::Any::Adapter::Test->clear

       This class method removes all of the stored values of reported metrics.

   override_timer_duration
          Metrics::Any::Adapter::Test->override_timer_duration( $duration )

       This class method sets a duration value, that any subsequent call to "inc_timer" will use instead of the
       value the caller actually passed in. This will ensure reliably predictable output in unit tests.

       Any value set here will be cleared by "clear".

       "Metrics::Any::Adapter::Test" - a metrics reporting adapter for unit testing

          use Test2::V0;
          use Metrics::Any::Adapter 'Test';

          {
             Metrics::Any::Adapter::Test->clear;

             # perform some work in the code under test

             is( Metrics::Any::Adapter::Test->metrics,
                "an_expected_metric = 1\n",
                'Metrics were reported while doing something'
             );
          }