NAME

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

SYNOPSIS

   use Test::More;
   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'
      );
   }

DESCRIPTION

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 the count and total duration.

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

METHODS

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

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".

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>