=head1 DESCRIPTION
- AHHHHHHH!!!! NOT B<TESTING>! Anything but testing!
- Beat me, whip me, send me to I<Detroit>, but don't make
- me write tests!
- *sob*
+I<AHHHHHHH!!!! NOT TESTING! Anything but testing!
+Beat me, whip me, send me to Detroit, but don't make
+me write tests!>
+
+I<*sob*>
+
+I<Besides, I don't know how to write the damned things.>
- Besides, I don't know how to write the damned things.
Is this you? Is writing tests right up there with writing
-documentation and having your fingernails pulled out?
+documentation and having your fingernails pulled out? Did you open up
+a test and read
+
+ ######## We start with some black magic
+
+and decide that's quite enough for you?
+
+It's ok. That's all gone now. We've done all the black magic for
+you. And here are the tricks...
=head2 Nuts and bolts of testing.
What this says is: C<1..1> "I'm going to run one test." [1] C<ok 1>
"The first test passed". And that's about all magic there is to
-testing. Your basic unit of testing is the 'ok'. For each thing you
-test, an 'ok' is printed. Simple. Test::Harness interprets your test
+testing. Your basic unit of testing is the I<ok>. For each thing you
+test, an C<ok> is printed. Simple. B<Test::Harness> interprets your test
results to determine if you succeeded or failed (more on that later).
Writing all these print statements rapidly gets tedious. Fortunately,
-there's Test::Simple. It has one function, ok().
+there's B<Test::Simple>. It has one function, C<ok()>.
#!/usr/bin/perl -w
ok( 1 + 1 == 2 );
-and that does the same thing as the code above. ok() is the backbone
+and that does the same thing as the code above. C<ok()> is the backbone
of Perl testing, and we'll be using it instead of roll-your-own from
-here on. If ok() gets a true value, the test passes. False, it
+here on. If C<ok()> gets a true value, the test passes. False, it
fails.
#!/usr/bin/perl -w
C<1..2> "I'm going to run two tests." This number is used to ensure
your test program ran all the way through and didn't die or skip some
tests. C<ok 1> "The first test passed." C<not ok 2> "The second test
-failed". Test::Simple helpfuly prints out some extra commentary about
+failed". Test::Simple helpfully prints out some extra commentary about
your tests.
It's not scary. Come, hold my hand. We're going to give an example
of testing a module. For our example, we'll be testing a date
-library, Date::ICal. It's on CPAN, so download a copy and follow
+library, B<Date::ICal>. It's on CPAN, so download a copy and follow
along. [2]
get overwhelmed at the apparent enormity of the task of testing a
whole module. Best place to start is at the beginning. Date::ICal is
an object-oriented module, and that means you start by making an
-object. So we test new().
+object. So we test C<new()>.
#!/usr/bin/perl -w
tests you can figure out which one is #2, but what if you have 102?
Each test can be given a little descriptive name as the second
-argument to ok().
+argument to C<ok()>.
use Test::Simple tests => 2;
=head2 Test the manual
Simplest way to build up a decent testing suite is to just test what
-the manual says it does. [3] Let's pull something out of of the
-Date::ICal SYNOPSIS and test that all it's bits work.
+the manual says it does. [3] Let's pull something out of the
+L<Date::ICal/SYNOPSIS> and test that all its bits work.
#!/usr/bin/perl -w
# Looks like you failed 1 tests of 8.
Whoops, a failure! [4] Test::Simple helpfully lets us know on what line
-the failure occured, but not much else. We were supposed to get 17,
+the failure occurred, but not much else. We were supposed to get 17,
but we didn't. What did we get?? Dunno. We'll have to re-run the
test in the debugger or throw in some print statements to find out.
-Instead, we'll switch from Test::Simple to Test::More. Test::More
-does everything Test::Simple does, and more! In fact, Test::More does
+Instead, we'll switch from B<Test::Simple> to B<Test::More>. B<Test::More>
+does everything B<Test::Simple> does, and more! In fact, Test::More does
things I<exactly> the way Test::Simple does. You can literally swap
Test::Simple out and put Test::More in its place. That's just what
we're going to do.
-Test::More provides more informative ways to say 'ok'. ok() is nice
-and generic, you can write almost any test with it, but it can't tell
-you what went wrong. For that, we use the is() function.
+Test::More does more than Test::Simple. The most important difference
+at this point is it provides more informative ways to say "ok".
+Although you can write almost any test with a generic C<ok()>, it
+can't tell you what went wrong. Instead, we'll use the C<is()>
+function, which lets us declare that something is supposed to be the
+same as something else:
#!/usr/bin/perl -w
is( $ical->month, 10, ' month()' );
is( $ical->year, 1964, ' year()' );
-"Is C<$ical->sec> 47?" "Is C<$ical->min> 12?" With is() in place,
+"Is C<$ical-E<gt>sec> 47?" "Is C<$ical-E<gt>min> 12?" With C<is()> in place,
you get some more information
1..8
ok 8 - year()
# Looks like you failed 1 tests of 8.
-letting us know that $ical->day returned 16, but we expected 17. A
+letting us know that C<$ical-E<gt>day> returned 16, but we expected 17. A
quick check shows that the code is working fine, we made a mistake
when writing up the tests. Just change it to:
and everything works.
-So any time you're doing a "this equals that" sort of test, use is().
+So any time you're doing a "this equals that" sort of test, use C<is()>.
It even works on arrays. The test is always in scalar context, so you
can test how many elements are in a list this way. [5]
}
So now we can test bunches of dates by just adding them to
-%ICal_Dates. Now that it's less work to test with more dates, you'll
+C<%ICal_Dates>. Now that it's less work to test with more dates, you'll
be inclined to just throw more in as you think of them.
Only problem is, every time we add to that we have to keep adjusting
-the C<use Test::More tests => ##> line. That can rapidly get
-annoying. Instead we use 'no_plan'. This means we're just running
-some tests, don't know how many. [6]
+the C<use Test::More tests =E<gt> ##> line. That can rapidly get
+annoying. There's two ways to make this work better.
+
+First, we can calculate the plan dynamically using the C<plan()>
+function.
+
+ use Test::More;
+ use Date::ICal;
+
+ my %ICal_Dates = (
+ ...same as before...
+ );
+
+ # For each key in the hash we're running 8 tests.
+ plan tests => keys %ICal_Dates * 8;
+
+Or to be even more flexible, we use C<no_plan>. This means we're just
+running some tests, don't know how many. [6]
use Test::More 'no_plan'; # instead of tests => 32
will make tracking down the problem easier. So try to put a bit of
debugging information into the test names.
+Describe what the tests test, to make debugging a failed test easier
+for you or for the next person who runs your test.
+
=head2 Skipping tests
Poking around in the existing Date::ICal tests, I found this in
-t/01sanity.t [7]
+F<t/01sanity.t> [7]
#!/usr/bin/perl -w
}
A little bit of magic happens here. When running on anything but
-MacOS, all the tests run normally. But when on MacOS, skip() causes
+MacOS, all the tests run normally. But when on MacOS, C<skip()> causes
the entire contents of the SKIP block to be jumped over. It's never
run. Instead, it prints special output that tells Test::Harness that
the tests have been skipped.
This means your tests won't fail on MacOS. This means less emails
from MacPerl users telling you about failing tests that you know will
never work. You've got to be careful with skip tests. These are for
-tests which don't work and B<never will>. It is not for skipping
+tests which don't work and I<never will>. It is not for skipping
genuine bugs (we'll get to that in a moment).
-The tests are wholely and completely skipped. [10] This will work.
+The tests are wholly and completely skipped. [10] This will work.
SKIP: {
skip("I don't wanna die!");
Retrieves, or sets, the date on the object, using any
valid ICal date/time string.
-"Retrieves or sets". Hmmm, didn't see a test for using ical() to set
+"Retrieves or sets". Hmmm, didn't see a test for using C<ical()> to set
the date in the Date::ICal test suite. So I'll write one.
use Test::More tests => 1;
+ use Date::ICal;
my $ical = Date::ICal->new;
$ical->ical('20201231Z');
Whoops! Looks like it's unimplemented. Let's assume we don't have
the time to fix this. [11] Normally, you'd just comment out the test
and put a note in a todo list somewhere. Instead, we're going to
-explicitly state "this test will fail" by wraping it in a TODO block.
+explicitly state "this test will fail" by wrapping it in a C<TODO> block.
use Test::More tests => 1;
you've fixed the underlying code.
If a TODO test passes, Test::Harness will report it "UNEXPECTEDLY
-SUCCEEDED". When that happens, you simply remove the TODO block and
+SUCCEEDED". When that happens, you simply remove the TODO block with
C<local $TODO> and turn it into a real test.
=head2 Testing with taint mode.
Taint mode is a funny thing. It's the globalest of all global
-features. Once you turn it on it effects B<all> code in your program
-and B<all> modules used (and all the modules they use). If a single
+features. Once you turn it on, it affects I<all> code in your program
+and I<all> modules used (and all the modules they use). If a single
piece of code isn't taint clean, the whole thing explodes. With that
in mind, it's very important to ensure your module works under taint
mode.
It's very simple to have your tests run under taint mode. Just throw
-a -T into the #! line. Test::Harness will read the switches in #! and
-use them to run your tests.
+a C<-T> into the C<#!> line. Test::Harness will read the switches
+in C<#!> and use them to run your tests.
#!/usr/bin/perl -Tw
- use Test::More 'no_plan';
-
...test normally here...
-So when you say "make test" it will be run with taint mode and
+So when you say C<make test> it will be run with taint mode and
warnings on.
=item 3
You can actually take this one step further and test the manual
-itself. Have a look at Pod::Tests (soon to be Test::Inline).
+itself. Have a look at B<Test::Inline> (formerly B<Pod::Tests>).
=item 4
bugs!
=back
+
+=head1 AUTHORS
+
+Michael G Schwern E<lt>schwern@pobox.comE<gt> and the perl-qa dancers!
+
+=head1 COPYRIGHT
+
+Copyright 2001 by Michael G Schwern E<lt>schwern@pobox.comE<gt>.
+
+This documentation is free; you can redistribute it and/or modify it
+under the same terms as Perl itself.
+
+Irrespective of its distribution, all code examples in these files
+are hereby placed into the public domain. You are permitted and
+encouraged to use this code in your own programs for fun
+or for profit as you see fit. A simple comment in the code giving
+credit would be courteous but is not required.
+
+=cut
projects / p5sagit/p5-mst-13.2.git / blobdiff