IO::Async::Test(3)

NAME
"IO::Async::Test" - utility functions for use in test scripts

SYNOPSIS
 use Test::More tests => 1;
 use IO::Async::Test;

 use IO::Async::Loop;
 my $loop = IO::Async::Loop->new;
 testing_loop( $loop );

 my $result;

 $loop->do_something(
    some => args,

    on_done => sub {
       $result = the_outcome;
    }
 );

 wait_for { defined $result };

 is( $result, what_we_expected, 'The event happened' );

 ...

 my $buffer = "";
 my $handle = IO::Handle-> ...

 wait_for_stream { length $buffer >= 10 } $handle => $buffer;

 is( substr( $buffer, 0, 10, "" ), "0123456789", 'Buffer was correct' );

DESCRIPTION
This module provides utility functions that may be useful when writing test scripts for code which uses "IO::Async" (as well as being used in the "IO::Async" test scripts themselves).

Test scripts are often synchronous by nature; they are a linear sequence of actions to perform, interspersed with assertions which check for given conditions. This goes against the very nature of "IO::Async" which, being an asynchronisation framework, does not provide a linear stepped way of working.

In order to write a test, the "wait_for" function provides a way of synchronising the code, so that a given condition is known to hold, which would typically signify that some event has occured, the outcome of which can now be tested using the usual testing primitives.

Because the primary purpose of "IO::Async" is to provide IO operations on filehandles, a great many tests will likely be based around connected pipes or socket handles. The "wait_for_stream" function provides a convenient way to wait for some content to be written through such a connected stream.

FUNCTIONS

  testing_loop( $loop )
Set the "IO::Async::Loop" object which the "wait_for" function will loop on.

  wait_for( $condfunc )
Repeatedly call the "loop_once" method on the underlying loop (given to the "testing_loop" function), until the given condition function callback returns true.

To guard against stalled scripts, if the loop indicates a timeout for 10 consequentive seconds, then an error is thrown.

  wait_for_stream( $condfunc, $handle, $buffer )
As "wait_for", but will also watch the given IO handle for readability, and whenever it is readable will read bytes in from it into the given buffer. The buffer is NOT initialised when the function is entered, in case data remains from a previous call.

$buffer can also be a CODE reference, in which case it will be invoked being passed data read from the handle, whenever it is readable.

AUTHOR
Paul Evans <leonerd@leonerd.org.uk>