Perl 5 version 30.0 documentation
Test::Builder::Tester - test testsuites that have been built with Test::Builder
A module that helps you test testing modules that are built with Test::Builder.
The testing system is designed to be used by performing a three step
process for each test you wish to test. This process starts with using
in advance to declare what the testsuite you
are testing will output with Test::Builder to stdout and stderr.
You then can run the test(s) from your test suite that call Test::Builder. At this point the output of Test::Builder is safely captured by Test::Builder::Tester rather than being interpreted as real test output.
The final stage is to call
that will simply compare what you
predeclared to what Test::Builder actually outputted, and report the
results back with a "ok" or "not ok" (with debugging) to the normal
These are the six methods that are exported as default.
Procedures for predeclaring the output that your test suite is expected to produce until
test_testis called. These procedures automatically assume that each line terminates with "\n". So
- test_out("ok 1","ok 2");
is the same as
- test_out("ok 1\nok 2");
which is even the same as
- test_out("ok 1");
- test_out("ok 2");
test_diag) have been called, all further output from Test::Builder will be captured by Test::Builder::Tester. This means that you will not be able perform further tests to the normal output in the normal way until you call
test_test(well, unless you manually meddle with the output filehandles)
Because the standard failure message that Test::Builder produces whenever a test fails will be a common occurrence in your test error output, and because it has changed between Test::Builder versions, rather than forcing you to call
test_errwith the string all the time like so
- test_err("# Failed test ($0 at line ".line_num(+1).")");
test_failexists as a convenience function that can be called instead. It takes one argument, the offset from the current line that the line that causes the fail is on.
This means that the example in the synopsis could be rewritten more simply as:
- test_out("not ok 1 - foo");
- test_test("fail works");
As most of the remaining expected output to the error stream will be created by Test::Builder's
diagfunction, Test::Builder::Tester provides a convenience function
test_diagthat you can use instead of
test_diagfunction prepends comment hashes and spacing to the start and newlines to the end of the expected output passed to it and adds it to the list of expected error output. So, instead of writing
- test_err("# Couldn't open file");
you can write
- test_diag("Couldn't open file");
Remember that Test::Builder's diag function will not add newlines to the end of output and test_diag will. So to check
You would do
without the newlines.
This takes name/value pairs that effect how the test is run.
- title (synonym 'name', 'label')
The name of the test that will be displayed after the
Setting this to a true value will cause the test to ignore if the output sent by the test to the output stream does not match that declared with
Setting this to a true value will cause the test to ignore if the output sent by the test to the error stream does not match that declared with
As a convenience, if only one argument is passed then this argument is assumed to be the name of the test (as in the above examples.)
test_testhas been run test output will be redirected back to the original filehandles that Test::Builder was connected to (probably STDOUT and STDERR,) meaning any further tests you run will function normally and cause success/errors for Test::Harness.
- title (synonym 'name', 'label')
A utility function that returns the line number that the function was called on. You can pass it an offset which will be added to the result. This is very useful for working out the correct text of diagnostic functions that contain line numbers.
Essentially this is the same as the
__LINE__macro, but the
line_num(+3)idiom is arguably nicer.
In addition to the six exported functions there exists one function that can only be accessed with a fully qualified function call.
test_testis called and the output that your tests generate does not match that which you declared,
test_testwill print out debug information showing the two conflicting versions. As this output itself is debug information it can be confusing which part of the output is from
test_testand which was the original output from your original tests. Also, it may be hard to spot things like extraneous whitespace at the end of lines that may cause your test to fail even though the output looks similar.
To assist you
test_testcan colour the background of the debug information to disambiguate the different types of output. The debug output will have its background coloured green and red. The green part represents the text which is the same between the executed and actual output, the red shows which part differs.
colorfunction determines if colouring should occur or not. Passing it a true or false value will enable or disable colouring respectively, and the function called with no argument will return the current setting.
To enable colouring from the command line, you can use the Text::Builder::Tester::Color module like so:
- perl -Mlib=Text::Builder::Tester::Color test.t
Or by including the Test::Builder::Tester::Color module directly in the PERL5LIB.
Test::Builder::Tester does not handle plans well. It has never done anything
special with plans. This means that plans from outside Test::Builder::Tester
will effect Test::Builder::Tester, worse plans when using Test::Builder::Tester
will effect overall testing. At this point there are no plans to fix this bug
as people have come to depend on it, and Test::Builder::Tester is now
discouraged in favor of
turning off the ending tests.
This is needed as otherwise it will trip out because we've run more
tests than we strictly should have and it'll register any failures we
had that we were testing for as real failures.
Bugs (and requests for new features) can be reported to the author though GitHub: https://github.com/Test-More/test-more/issues
Copyright Mark Fowler <email@example.com> 2002, 2004.
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
Thanks to Richard Clamp <firstname.lastname@example.org> for letting me use his testing system to try this module out on.