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Test::SubCalls(3) User Contributed Perl Documentation Test::SubCalls(3)


Test::SubCalls - Track the number of times subs are called


version 1.10


  use Test::SubCalls;
  # Start tracking calls to a named sub
  sub_track( 'Foo::foo' );
  # Run some test code
  # Test that some sub deep in the codebase was called
  # a specific number of times.
  sub_calls( 'Foo::foo', 5 );
  sub_calls( 'Foo::foo', 5, 'Use a custom test message' );
  # Reset the counts for one or all subs
  sub_reset( 'Foo::foo' );


There are a number of different situations (like testing caching code) where you want to want to do a number of tests, and then verify that some underlying subroutine deep within the code was called a specific number of times.

This module provides a number of functions for doing testing in this way in association with your normal Test::More (or similar) test scripts.


In the nature of test modules, all functions are exported by default.

sub_track $subname

The "sub_track" function creates a new call tracker for a named function.

The sub to track must be provided by name, references to the function itself are insufficient.

Returns true if added, or dies on error.

sub_calls $subname, $expected_calls [, $message ]

The "sub_calls" function is the primary (and only) testing function provided by "Test::SubCalls". A single call will represent one test in your plan.

It takes the subroutine name as originally provided to "sub_track", the expected number of times the subroutine should have been called, and an optional test message.

If no message is provided, a default message will be provided for you.

Test is ok if the number of times the sub has been called matches the expected number, or not ok if not.

sub_reset $subname

To prevent repeat users from having to take before and after counts when they start testing from after zero, the "sub_reset" function has been provided to reset a sub call counter to zero.

Returns true or dies if the sub name is invalid or not currently tracked.


Provided mainly as a convenience, the "sub_reset_all" function will reset all the counters currently defined.

Returns true.


Bugs should be submitted via the CPAN bug tracker, located at


For other issues, or commercial enhancement or support, contact the author.


Adam Kennedy <>


<>, Test::Builder, Test::More, Hook::LexWrap


Copyright 2005 - 2009 Adam Kennedy.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

The full text of the license can be found in the LICENSE file included with this module.

2017-12-24 perl v5.40.0