The test_expect() subroutine splits an input document into a number of separate tests, processes each one using the Template Toolkit and then compares the generated output against an expected output, also specified in the input document. It generates the familiar ok/not ok output compatible with Test::Harness.

The test input should be specified as a text string or a reference to a filehandle (e.g. GLOB or IO::Handle) from which it can be read. In particular, this allows the test input to be placed after the __END__ marker and read via the DATA filehandle.

use Template::Test;

test_expect(\*DATA);

__END__
# this is the first test (this is a comment)
-- test --
blah blah blah [% foo %]
-- expect --
blah blah blah value_of_foo

# here's the second test (no surprise, so is this)
-- test --
more blah blah [% bar %]
-- expect --
more blah blah value_of_bar

Blank lines between test sections are generally ignored. Any line starting with # is treated as a comment and is ignored.

The second and third parameters to test_expect() are optional. The second may be either a reference to a Template object which should be used to process the template fragments, or a reference to a hash array containing configuration values which should be used to instantiate a new Template object.

# pass reference to config hash
my $config = {
    INCLUDE_PATH => '/here/there:/every/where',
    POST_CHOMP   => 1,
};
test_expect(\*DATA, $config);

# or create Template object explicitly
my $template = Template->new($config);
test_expect(\*DATA, $template);

The third parameter may be used to reference a hash array of template variable which should be defined when processing the tests. This is passed to the Template process() method.

my $replace = {
    a => 'alpha',
    b => 'bravo',
};

test_expect(\*DATA, $config, $replace);

The second parameter may be left undefined to specify a default Template configuration.

test_expect(\*DATA, undef, $replace);

For testing the output of different Template configurations, a reference to a list of named Template objects also may be passed as the second parameter.

my $tt1 = Template->new({ ... });
my $tt2 = Template->new({ ... });
my @tts = [ one => $tt1, two => $tt1 ];

The first object in the list is used by default. Other objects may be switched in with a '-- use $name --' marker. This should immediately follow a '-- test --' line. That object will then be used for the rest of the test, or until a different object is selected.

-- test --
-- use one --
[% blah %]
-- expect --
blah, blah

-- test --
still using one...
-- expect --
...

-- test --
-- use two --
[% blah %]
-- expect --
blah, blah, more blah

The test_expect() sub counts the number of tests, and then calls ntests() to generate the familiar "1..$ntests\n" test harness line. Each test defined generates two test numbers. The first indicates that the input was processed without error, and the second that the output matches that expected.

Additional test may be run before test_expect() by calling ok(). These test results are cached until ntests() is called and the final number of tests can be calculated. Then, the "1..$ntests" line is output, along with "ok $n" / "not ok $n" lines for each of the cached test result. Subsequent calls to ok() then generate an output line immediately.

my $something = SomeObject->new();
ok( $something );

my $other = AnotherThing->new();
ok( $other );

test_expect(\*DATA);

If any tests are to follow after test_expect() is called then these should be pre-declared by setting the $EXTRA package variable. This value (default: 0) is added to the grand total calculated by ntests(). The results of the additional tests are also registered by calling ok().

$Template::Test::EXTRA = 2;

# can call ok() any number of times before test_expect()
ok( $did_that_work );             
ok( $make_sure );
ok( $dead_certain ); 

# <some> number of tests...
test_expect(\*DATA, $config, $replace);

# here's those $EXTRA tests
ok( defined $some_result && ref $some_result eq 'ARRAY' );
ok( $some_result->[0] eq 'some expected value' );

If you don't want to call test_expect() at all then you can call ntests($n) to declare the number of tests and generate the test header line. After that, simply call ok() for each test passing a true or false values to indicate that the test passed or failed.

ntests(2);
ok(1);
ok(0);

If you're really lazy, you can just call ok() and not bother declaring the number of tests at all. All tests results will be cached until the end of the script and then printed in one go before the program exits.

ok( $x );
ok( $y );

You can identify only a specific part of the input file for testing using the '-- start --' and '-- stop --' markers. Anything before the first '-- start --' is ignored, along with anything after the next '-- stop --' marker.

-- test --
this is test 1 (not performed)
-- expect --
this is test 1 (not performed)

-- start --

-- test --
this is test 2
-- expect --
this is test 2

-- stop --

...

Subroutine used to specify how many tests you're expecting to run.

Generates an "ok $n" or "not ok $n" message if $test is true or false.

The logical inverse of ok(). Prints an "ok $n" message is $test is false and vice-versa.

For historical reasons and general utility, the module also defines a callsign() subroutine which returns a hash mapping the letters a to z to their phonetic alphabet equivalent (e.g. radio callsigns). This is used by many of the test scripts as a known source of variable values.

test_expect(\*DATA, $config, callsign());

This subroutine prints a simple banner including any text passed as parameters. The $DEBUG variable must be set for it to generate any output.

banner('Testing something-or-other');

example output:

#------------------------------------------------------------
# Testing something-or-other (27 tests completed)
#------------------------------------------------------------

The $DEBUG package variable can be set to enable debugging mode.

The $PRESERVE package variable can be set to stop the test_expect() from converting newlines in the output and expected output into the literal strings '\n'.