1Test::Deep(3) User Contributed Perl Documentation Test::Deep(3)
2
6 Test::Deep - Extremely flexible deep comparison
7
9 use Test::More tests => $Num_Tests;
10 use Test::Deep;
11 cmp_deeply(
13 $actual_horrible_nested_data_structure,
14 $expected_horrible_nested_data_structure,
15 "got the right horrible nested data structure"
16 );
17 cmp_deeply(
19 $object,
20 methods(name => "John", phone => "55378008"),
21 "object methods ok"
22 );
23 cmp_deeply(
25 \@array,
26 [$hash1, $hash2, ignore()],
27 "first 2 elements are as expected, ignoring 3"
28 );
29 cmp_deeply(
31 $object,
32 noclass({value => 5}),
33 "object looks ok, not checking its class"
34 );
35 cmp_deeply(
37 \@result,
38 bag('a', 'b', {key => [1, 2]}),
39 "array has the 3 things we wanted in some order"
40 );
41
43 If you don't know anything about automated testing in Perl then you
44 should probably read about Test::Simple and Test::More before
45 preceding. Test::Deep uses the Test::Builder framework.
46 Test::Deep gives you very flexible ways to check that the result you
48 got is the result you were expecting. At its simplest it compares two
49 structures by going through each level, ensuring that the values match,
50 that arrays and hashes have the same elements and that references are
51 blessed into the correct class. It also handles circular data
52 structures without getting caught in an infinite loop.
53 Where it becomes more interesting is in allowing you to do something
55 besides simple exact comparisons. With strings, the "eq" operator
56 checks that 2 strings are exactly equal but sometimes that's not what
57 you want. When you don't know exactly what the string should be but you
58 do know some things about how it should look, "eq" is no good and you
59 must use pattern matching instead. Test::Deep provides pattern matching
60 for complex data structures
61 Test::Deep has a lot of exports. See "EXPORTS" below.
63
65 How Test::Deep works is much easier to understand by seeing some
66 examples.
67 Without Test::Deep
69 Say you want to test a function which returns a string. You know that
70 your string should be a 7 digit number beginning with 0, "eq" is no
71 good in this situation, you need a regular expression. So you could use
72 Test::More's "like()" function:
73 like($string, qr/^0[0-9]{6}$/, "number looks good");
75 Similarly, to check that a string looks like a name, you could do:
77 like($string, qr/^(Mr|Mrs|Miss) \w+ \w+$/,
79 "got title, first and last name");
80 Now imagine your function produces a hash with some personal details in
82 it. You want to make sure that there are 2 keys, Name and Phone and
83 that the name looks like a name and the phone number looks like a phone
84 number. You could do:
85 $hash = make_person();
87 like($hash->{Name}, qr/^(Mr|Mrs|Miss) \w+ \w+$/, "name ok");
88 like($hash->{Phone}, qr/^0[0-9]{6}$/, "phone ok");
89 is(scalar keys %$hash, 2, "correct number of keys");
90 But that's not quite right, what if make_person has a serious problem
92 and didn't even return a hash? We really need to write
93 if (ref($hash) eq "HASH")
95 {
96 like($hash->{Name}, qr/^(Mr|Mrs|Miss) \w+ \w+$/, "name ok");
97 like($hash->{Phone}, qr/^0[0-9]{6}$/, "phone ok");
98 is(scalar keys %$hash, 2, "correct number of keys");
99 }
100 else
101 {
102 fail("person not a hash");
103 fail("person not a hash");
104 fail("person not a hash"); # need 3 to keep the plan correct
105 }
106 Already this is getting messy, now imagine another entry in the hash,
108 an array of children's names. This would require
109 if (ref($hash) eq "HASH")
111 {
112 like($hash->{Name}, $name_pat, "name ok");
113 like($hash->{Phone}, '/^0d{6}$/', "phone ok");
114 my $cn = $hash->{ChildNames};
115 if (ref($cn) eq "ARRAY")
116 {
117 foreach my $child (@$cn)
118 {
119 like($child, $name_pat);
120 }
121 }
122 else
123 {
124 fail("child names not an array")
125 }
126 }
127 else
128 {
129 fail("person not a hash");
130 }
131 This is a horrible mess and because we don't know in advance how many
133 children's names there will be, we can't make a plan for our test
134 anymore (actually, we could but it would make things even more
135 complicated).
136 Test::Deep to the rescue.
138 With Test::Deep
140 my $name_re = re('^(Mr|Mrs|Miss) \w+ \w+$');
141 cmp_deeply(
142 $person,
143 {
144 Name => $name_re,
145 Phone => re('^0d{6}$'),
146 ChildNames => array_each($name_re)
147 },
148 "person ok"
149 );
150 This will do everything that the messy code above does and it will give
152 a sensible message telling you exactly what went wrong if it finds a
153 part of $person that doesn't match the pattern. "re()" and
154 "array_each()" are special function imported from Test::Deep. They
155 create a marker that tells Test::Deep that something different is
156 happening here. Instead of just doing a simple comparison and checking
157 are two things exactly equal, it should do something else.
158 If a person was asked to check that 2 structures are equal, they could
160 print them both out and compare them line by line. The markers above
161 are similar to writing a note in red pen on one of the printouts
162 telling the person that for this piece of the structure, they should
163 stop doing simple line by line comparison and do something else.
164 "re($regex)" means that Test::Deep should check that the current piece
166 of data matches the regex in $regex. "array_each($struct)" means that
167 Test::Deep should expect the current piece of data to be an array and
168 it should check that every element of that array matches $struct. In
169 this case, every element of "$person->{ChildNames}" should look like a
170 name. If say the 3rd one didn't you would get an error message
171 something like
172 Using Regexp on $data->{ChildNames}[3]
174 got : 'Queen John Paul Sartre'
175 expect : /^(Mr|Mrs|Miss) \w+ \w+$/
176 There are lots of other special comparisons available, see "SPECIAL
178 COMPARISONS PROVIDED" below for the full list.
179 Reusing structures
181 Test::Deep is good for reusing test structures so you can do this
182 my $name_re = re('^(Mr|Mrs|Miss) \w+ \w+$');
184 my $person_cmp = {
185 Name => $name_re,
186 Phone => re('^0d{6}$'),
187 ChildNames => array_each($name_re)
188 };
189 cmp_deeply($person1, $person_cmp, "person ok");
191 cmp_deeply($person2, $person_cmp, "person ok");
192 cmp_deeply($person3, $person_cmp, "person ok");
193 You can even put $person_cmp in a module and let other people use it
195 when they are writing test scripts for modules that use your modules.
196 To make things a little more difficult, lets change the person data
198 structure so that instead of a list of ChildNames, it contains a list
199 of hashes, one for each child. So in fact our person structure will
200 contain other person structures which may contain other person
201 structures and so on. This is easy to handle with Test::Deep because
202 Test::Deep structures can include themselves. Simply do
203 my $name_re = re('^(Mr|Mrs|Miss) \w+ \w+$');
205 my $person_cmp = {
206 Name => $name_re,
207 Phone => re('^0d{6}$'),
208 # note no mention of Children here
209 };
210 $person_cmp->{Children} = array_each($person_cmp);
212 cmp_deeply($person, $person_cmp, "person ok");
214 This will now check that $person->{Children} is an array and that every
216 element of that array also matches $person_cmp, this includes checking
217 that its children also match the same pattern and so on.
218 Circular data structures
220 A circular data structure is one which loops back on itself, you can
221 make one easily by doing
222 my @b;
224 my @a = (1, 2, 3, \@b);
225 push(@b, \@a);
226 now @a contains a reference to be @b and @b contains a reference to @a.
228 This causes problems if you have a program that wants to look inside @a
229 and keep looking deeper and deeper at every level, it could get caught
230 in an infinite loop looking into @a then @b then @a then @b and so on.
231 Test::Deep avoids this problem so we can extend our example further by
233 saying that a person should also list their parents.
234 my $name_re = re('^(Mr|Mrs|Miss) \w+ \w+$');
236 my $person_cmp = {
237 Name => $name_re,
238 Phone => re('^0d{6}$'),
239 # note no mention of Children here
240 };
241 $person_cmp->{Children} = each_array($person_cmp);
243 $person_cmp->{Parents} = each_array($person_cmp);
244 cmp_deeply($person, $person_cmp, "person ok");
246 So this will check that for each child $child in "$person->{Children}"
248 that the "$child->{Parents}" matches $person_cmp however it is smart
249 enough not to get caught in an infinite loop where it keeps bouncing
250 between the same Parent and Child.
251
253 "cmp_deeply($got, $expected, $name)" takes 3 arguments. $got is the
254 structure that you are checking, you must not include any special
255 comparisons in this structure or you will get a fatal error. $expected
256 describes what Test::Deep will be looking for in $got. You can put
257 special comparisons in $expected if you want to.
258 As Test::Deep descends through the 2 structures, it compares them one
260 piece at a time, so at any point in the process, Test::Deep is thinking
261 about 2 things - the current value from $got and the current value from
262 $expected. In the documentation, I call them $got_v and "exp_v"
263 respectively.
264
266 cmp_deeply
267 my $ok = cmp_deeply($got, $expected, $name)
269 $got is the result to be checked. $expected is the structure against
271 which $got will be check. $name is the test name.
272 This is the main comparison function, the others are just wrappers
274 around this. $got and $expected are compared recursively. Each value
275 in $expected defines what's expected at the corresponding location in
276 $got. Simple scalars are compared with "eq". References to structures
277 like hashes and arrays are compared recursively.
278 Items in $expected, though, can also represent complex tests that check
280 for numbers in a given range, hashes with at least a certain set of
281 keys, a string matching a regex, or many other things.
282 See "WHAT ARE SPECIAL COMPARISONS" for details.
284 cmp_bag
286 my $ok = cmp_bag(\@got, \@bag, $name)
288 Is shorthand for cmp_deeply(\@got, bag(@bag), $name)
290 n.b.: Both arguments must be array refs. If they aren't an exception
292 will be thrown.
293 cmp_set
295 my $ok = cmp_set(\@got, \@set, $name)
297 Is shorthand for cmp_deeply(\@got, set(@set), $name)
299 cmp_methods
301 my $ok = cmp_methods(\@got, \@methods, $name)
303 Is shorthand for cmp_deeply(\@got, methods(@methods), $name)
305 eq_deeply
307 my $ok = eq_deeply($got, $expected)
309 This is the same as cmp_deeply() except it just returns true or false.
311 It does not create diagnostics or talk to Test::Builder, but if you
312 want to use it in a non-testing environment then you should import it
313 through Test::Deep::NoTest. For example
314 use Test::Deep::NoTest;
316 print "a equals b" unless eq_deeply($a, $b);
317 otherwise the Test::Builder framework will be loaded and testing
319 messages will be output when your program ends.
320 cmp_details
322 ($ok, $stack) = cmp_details($got, $expected)
324 This behaves much like eq_deeply, but it additionally allows you to
326 produce diagnostics in case of failure by passing the value in $stack
327 to "deep_diag".
328 Do not make assumptions about the structure or content of $stack and do
330 not use it if $ok contains a true value.
331 See "USING TEST::DEEP WITH TEST::BUILDER" for example uses.
333
335 In the documentation below, $got_v is used to indicate any given value
336 within the $got structure.
337 ignore
339 cmp_deeply( $got, ignore() );
341 This makes Test::Deep skip tests on $got_v. No matter what value $got_v
343 has, Test::Deep will think it's correct. This is useful if some part of
344 the structure you are testing is very complicated and already tested
345 elsewhere, or if it is unpredictable.
346 cmp_deeply(
348 $got,
349 {
350 name => 'John',
351 random => ignore(),
352 address => [ '5 A street', 'a town', 'a country' ],
353 }
354 );
355 is the equivalent of checking
357 $got->{name} eq 'John';
359 exists $got->{random};
360 cmp_deeply($got->{address}, ['5 A street', 'a town', 'a country']);
361 methods
363 cmp_deeply( $got, methods(%hash) );
365 %hash is a hash of method call => expected value pairs.
367 This lets you call methods on an object and check the result of each
369 call. The methods will be called in the order supplied. If you want to
370 pass arguments to the method you should wrap the method name and
371 arguments in an array reference.
372 cmp_deeply(
374 $obj,
375 methods(name => "John", ["favourite", "food"] => "taco")
376 );
377 is roughly the equivalent of checking that
379 $obj->name eq "John"
381 $obj->favourite("food") eq "taco"
382 The methods will be called in the order you supply them and will be
384 called in scalar context. If you need to test methods called in list
385 context then you should use "listmethods()".
386 NOTE Just as in a normal test script, you need to be careful if the
388 methods you call have side effects like changing the object or other
389 objects in the structure. Although the order of the methods is fixed,
390 the order of some other tests is not so if $expected is
391 {
393 manager => methods(@manager_methods),
394 coder => methods(@coder_methods)
395 }
396 there is no way to know which if manager and coder will be tested
398 first. If the methods you are testing depend on and alter global
399 variables or if manager and coder are the same object then you may run
400 into problems.
401 listmethods
403 cmp_deeply( $got, listmethods(%hash) );
405 %hash is a hash of pairs mapping method names to expected return
407 values.
408 This is almost identical to methods() except the methods are called in
410 list context instead of scalar context. This means that the expected
411 return values supplied must be in array references.
412 cmp_deeply(
414 $obj,
415 listmethods(
416 name => [ "John" ],
417 ["favourites", "food"] => ["Mapo tofu", "Gongbao chicken"]
418 )
419 );
420 is the equivalent of checking that
422 cmp_deeply([$obj->name], ["John"]);
424 cmp_deeply([$obj->favourites("food")], ["Mapo tofu", "Gongbao chicken"]);
425 The methods will be called in the order you supply them.
427 NOTE The same caveats apply as for methods().
429 shallow
431 cmp_deeply( $got, shallow($thing) );
433 $thing is a ref.
435 This prevents Test::Deep from looking inside $thing. It allows you to
437 check that $got_v and $thing are references to the same variable. So
438 my @a = @b = (1, 2, 3);
440 cmp_deeply(\@a, \@b);
441 will pass because @a and @b have the same elements however
443 cmp_deeply(\@a, shallow(\@b))
445 will fail because although "\@a" and "\@b" both contain "1, 2, 3" they
447 are references to different arrays.
448 noclass
450 cmp_deeply( $got, noclass($thing) );
452 $thing is a structure to be compared against.
454 This makes Test::Deep ignore the class of objects, so it just looks at
456 the data they contain. Class checking will be turned off until
457 Test::Deep is finished comparing $got_v against $thing. Once Test::Deep
458 comes out of $thing it will go back to its previous setting for
459 checking class.
460 This can be useful when you want to check that objects have been
462 constructed correctly but you don't want to write lots of "bless"es. If
463 @people is an array of Person objects then
464 cmp_deeply(\@people, [
466 bless {name => 'John', phone => '555-5555'}, "Person",
467 bless {name => 'Anne', phone => '444-4444'}, "Person",
468 ]);
469 can be replaced with
471 cmp_deeply(\@people, noclass([
473 {name => 'John', phone => '555-5555'},
474 {name => 'Anne', phone => '444-4444'}
475 ]));
476 However, this is testing so you should also check that the objects are
478 blessed correctly. You could use a map to bless all those hashes or you
479 could do a second test like
480 cmp_deeply(\@people, array_each(isa("Person"));
482 useclass
484 cmp_deeply( $got, useclass($thing) );
486 This turns back on the class comparison while inside a "noclass()".
488 cmp_deeply(
490 $got,
491 noclass(
492 [
493 useclass( $object )
494 ]
495 )
496 )
497 In this example the class of the array reference in $got is ignored but
499 the class of $object is checked, as is the class of everything inside
500 $object.
501 re
503 cmp_deeply( $got, re($regexp, $capture_data, $flags) );
505 $regexp is either a regular expression reference produced with
507 "qr/.../" or a string which will be used to construct a regular
508 expression.
509 $capture_data is optional and is used to check the strings captured by
511 an regex. This should can be an array ref or a Test::Deep comparator
512 that works on array refs.
513 $flags is an optional string which controls whether the regex runs as a
515 global match. If $flags is "g" then the regex will run as
516 "m/$regexp/g".
517 Without $capture_data, this simply compares $got_v with the regular
519 expression provided. So
520 cmp_deeply($got, [ re("ferg") ])
522 is the equivalent of
524 $got->[0] =~ /ferg/
526 With $capture_data,
528 cmp_deeply($got, [re($regex, $capture_data)])
530 is the equivalent of
532 my @data = $got->[0] =~ /$regex/;
534 cmp_deeply(\@data, $capture_data);
535 So you can do something simple like
537 cmp_deeply($got, re(qr/(\d\d)(\w\w)/, [25, "ab" ]))
539 to check that "(\d\d)" was 25 and "(\w\w)" was "ab" but you can also
541 use Test::Deep objects to do more complex testing of the captured
542 values
543 cmp_deeply(
545 "cat=2,dog=67,sheep=3,goat=2,dog=5",
546 re(
547 qr/(\D+)=\d+,?/,
548 set(qw( cat sheep dog )),
549 "g"
550 ),
551 );
552 here, the regex will match the string and will capture the animal names
554 and check that they match the specified set, in this case it will fail,
555 complaining that "goat" is not in the set.
556 all
558 cmp_deeply( $got, all(@expecteds) );
560 @expecteds is an array of expected structures.
562 This allows you to compare data against multiple expected results and
564 make sure each of them matches.
565 cmp_deeply($got, all(isa("Person"), methods(name => 'John')))
567 is equivalent to
569 $got->isa("Person")
571 $got->name eq 'John'
572 If either test fails then the whole thing is considered a fail. This is
574 a short-circuit test, the testing is stopped after the first failure,
575 although in the future it may complete all tests so that diagnostics
576 can be output for all failures. When reporting failure, the parts are
577 counted from 1.
578 Thanks to the magic of overloading, you can write
580 any( re("^wi"), all(isa("Person"), methods(name => 'John')) )
582 as
584 re("^wi") | isa("Person") & methods(name => 'John')
586 Note single "|" not double, as "||" cannot be overloaded. This will
588 only work when there is a special comparison involved. If you write
589 "john" | "anne" | "robert"
591 Perl will turn this into
593 "{onort"
595 which is presumably not what you wanted. This is because perl ors them
597 together as strings before Test::Deep gets a chance to do any overload
598 tricks.
599 any
601 cmp_deeply( $got, any(@expecteds) );
603 @expecteds is an array of expected structures.
605 This can be used to compare data against multiple expected results and
607 make sure that at least one of them matches. This is a short-circuit
608 test so if a test passes then none of the tests after that will be
609 attempted.
610 You can also use overloading with "|" similarly to all().
612 Isa
614 cmp_deeply( $got, Isa($class) );
616 isa
618 cmp_deeply( $got, isa($class) );
620 $class is a class name.
622 This uses "UNIVERSAL::isa()" to check that $got_v is blessed into the
624 class $class.
625 NOTE: "Isa()" does exactly as documented here, but "isa()" is slightly
627 different. If "isa()" is called with 1 argument it falls through to
628 "Isa()". If "isa()" called with 2 arguments, it falls through to
629 "UNIVERSAL::isa". This is to prevent breakage when you import "isa()"
630 into a package that is used as a class. Without this, anyone calling
631 "Class->isa($other_class)" would get the wrong answer. This is a hack
632 to patch over the fact that "isa" is exported by default.
633 obj_isa
635 cmp_deeply( $got, obj_isa($class) );
637 This test accepts only objects that are instances of $class or a
639 subclass. Unlike the "Isa" test, this test will never accept class
640 names.
641 array_each
643 cmp_deeply( \@got, array_each($thing) );
645 $thing is a structure to be compared against.
647 <$got_v> must be an array reference. Each element of it will be
649 compared to $thing. This is useful when you have an array of similar
650 things, for example objects of a known type and you don't want to have
651 to repeat the same test for each one.
652 my $common_tests = all(
654 isa("MyFile"),
655 methods(
656 handle => isa("IO::Handle")
657 filename => re("^/home/ted/tmp"),
658 )
659 );
660 cmp_deeply($got, array_each($common_tests));
662 is similar to
664 foreach my $got_v (@$got) {
666 cmp_deeply($got_v, $common_tests)
667 }
668 Except it will not explode if $got is not an array reference. It will
670 check that each of the objects in @$got is a MyFile and that each one
671 gives the correct results for its methods.
672 You could go further, if for example there were 3 files and you knew
674 the size of each one you could do this
675 cmp_deeply(
677 $got,
678 all(
679 array_each($common_tests),
680 [
681 methods(size => 1000),
682 methods(size => 200),
683 methods(size => 20)
684 ]
685 )
686 )
687 cmp_deeply($got, array_each($structure));
688 hash_each
690 cmp_deeply( \%got, hash_each($thing) );
692 This test behaves like "array_each" (see above) but tests that each
694 hash value passes its tests.
695 str
697 cmp_deeply( $got, str($string) );
699 $string is a string.
701 This will stringify $got_v and compare it to $string using "eq", even
703 if $got_v is a ref. It is useful for checking the stringified value of
704 an overloaded reference.
705 num
707 cmp_deeply( $got, num($number, $tolerance) );
709 $number is a number.
711 $tolerance is an optional number.
713 This will add 0 to $got_v and check if it's numerically equal to
715 $number, even if $got_v is a ref. It is useful for checking the
716 numerical value of an overloaded reference. If $tolerance is supplied
717 then this will check that $got_v and $exp_v are less than $tolerance
718 apart. This is useful when comparing floating point numbers as rounding
719 errors can make it hard or impossible for $got_v to be exactly equal to
720 $exp_v. When $tolerance is supplied, the test passes if "abs($got_v -
721 $exp_v) <= $tolerance".
722 Note in Perl, ""12blah" == 12" because Perl will be smart and convert
724 "12blah" into 12. You may not want this. There was a strict mode but
725 that is now gone. A "looks like a number" test will replace it soon.
726 Until then you can usually just use the string() comparison to be more
727 strict. This will work fine for almost all situations, however it will
728 not work when <$got_v> is an overloaded value who's string and
729 numerical values differ.
730 bool, true, false
732 cmp_deeply( $got, bool($value) );
734 cmp_deeply( $got, true );
735 cmp_deeply( $got, false );
736 $value is anything you like but it's probably best to use 0 or 1
738 This will check that $got_v and $value have the same truth value, that
740 is they will give the same result when used in boolean context, like in
741 an "if()" statement.
742 Note: "true" and "false" are only imported by special request.
744 code
746 cmp_deeply( $got, code(\&subref) );
748 "\&subref" is a reference to a subroutine which will be passed a single
750 argument, it then should return a true or false and possibly a string
751 This will pass $got_v to the subroutine which returns true or false to
753 indicate a pass or fail. Fails can be accompanied by a diagnostic
754 string which gives an explanation of why it's a fail.
755 sub check_name
757 {
758 my $name = shift;
759 if ($boss->likes($name))
760 {
761 return 1;
762 }
763 else
764 {
765 return (0, "the boss doesn't like your name");
766 }
767 }
768 cmp_deeply("Brian", code(\&check_name));
770 SET COMPARISONS
772 Set comparisons give special semantics to array comparisons:
773 • The order of items in a set is irrelevant
775 • The presence of duplicate items in a set is ignored.
777 As such, in any set comparison, the following arrays are equal:
779 [ 1, 2 ]
781 [ 1, 1, 2 ]
782 [ 1, 2, 1 ]
783 [ 2, 1, 1 ]
784 [ 1, 1, 2 ]
785 All are interpreted by "set" semantics as if the set was only specified
787 as:
788 [ 1, 2 ]
790 All "set" functions return an object which can have additional items
792 added to it:
793 my $set = set( 1, 2 );
795 $set->add(1, 3, 1 ); # Set is now ( 1, 2, 3 )
796 Special care must be taken when using special comparisons within sets.
798 See "SPECIAL CARE WITH SPECIAL COMPARISONS IN SETS AND BAGS" for
799 details.
800 set
802 cmp_deeply( \@got, set(@elements) );
804 This does a set comparison, that is, it compares two arrays but ignores
806 the order of the elements and it ignores duplicate elements, but
807 ensures that all items in @elements will be in $got and all items in
808 $got will be in @elements.
809 So the following tests will be passes, and will be equivalent:
811 cmp_deeply([1, 2, 2, 3], set(3, 2, 1, 1));
813 cmp_deeply([1, 2, 3], set(3, 2, 1));
814 supersetof
816 cmp_deeply( \@got, supersetof(@elements) );
818 This function works much like "set", and performs a set comparison of
820 $got_v with the elements of @elements.
821 "supersetof" is however slightly relaxed, such that $got may contain
823 things not in @elements, but must at least contain all @elements.
824 These two statements are equivalent, and will be passes:
826 cmp_deeply([1,2,3,3,4,5], supersetof(2,2,3));
828 cmp_deeply([1,2,3,4,5], supersetof(2,3));
829 But these will be failures:
831 cmp_deeply([1,2,3,4,5], supersetof(2,3,6)); # 6 not in superset
833 cmp_deeply([1], supersetof(1,2)); # 2 not in superset
834 subsetof
836 cmp_deeply( \@got, subsetof(@elements) );
838 This function works much like "set", and performs a set comparison of
840 $got_v with the elements of @elements.
841 This is the inverse of "supersetof", which expects all unique elements
843 found in $got_v must be in @elements.
844 cmp_deeply([1,2,4,5], subsetof(2,3,3) ) # Fail: 1,4 & 5 extra
846 cmp_deeply([2,3,3], subsetof(1,2,4,5) ) # Fail: 3 extra
847 cmp_deeply([2,3,3], subsetof(1,2,4,5,3)) # Pass
848 none
850 cmp_deeply( $got, none(@elements) );
852 @elements is an array of elements, wherein no elements in @elements may
854 be equal to $got_v.
855 noneof
857 cmp_deeply( \@got, noneof(@elements) );
859 @elements is an array of elements, wherein no elements in @elements may
861 be found in $got_v.
862 For example:
864 # Got has no 1, no 2, and no 3
866 cmp_deeply( [1], noneof( 1, 2, 3 ) ); # fail
867 cmp_deeply( [5], noneof( 1, 2, 3 ) ); # pass
868 BAG COMPARISONS
870 Bag comparisons give special semantics to array comparisons, that are
871 similar to set comparisons, but slightly different.
872 • The order of items in a bag is irrelevant
874 • The presence of duplicate items in a bag is PRESERVED
876 As such, in any bag comparison, the following arrays are equal:
878 [ 1, 1, 2 ]
880 [ 1, 2, 1 ]
881 [ 2, 1, 1 ]
882 [ 1, 1, 2 ]
883 However, they are NOT equal to any of the following:
885 [ 1, 2 ]
887 [ 1, 2, 2 ]
888 [ 1, 1, 1, 2 ]
889 All "bag" functions return an object which can have additional items
891 added to it:
892 my $bag = bag( 1, 2 );
894 $bag->add(1, 3, 1 ); # Bag is now ( 1, 1, 1, 2, 3 )
895 Special care must be taken when using special comparisons within bags.
897 See "SPECIAL CARE WITH SPECIAL COMPARISONS IN SETS AND BAGS" for
898 details.
899 bag
901 cmp_deeply( \@got, bag(@elements) );
903 This does an order-insensitive bag comparison between $got and
905 @elements, ensuring that:
906 each item in @elements is found in $got
908 the number of times a $expected_v is found in @elements is reflected in
909 $got
910 no items are found in $got other than those in @elements.
911 As such, the following are passes, and are equivalent to each other:
913 cmp_deeply([1, 2, 2], bag(2, 2, 1))
915 cmp_deeply([2, 1, 2], bag(2, 2, 1))
916 cmp_deeply([2, 2, 1], bag(2, 2, 1))
917 But the following are failures:
919 cmp_deeply([1, 2, 2], bag(2, 2, 1, 1)) # Not enough 1's in Got
921 cmp_deeply([1, 2, 2, 1], bag(2, 2, 1) ) # Too many 1's in Got
922 superbagof
924 cmp_deeply( \@got, superbagof( @elements ) );
926 This function works much like "bag", and performs a bag comparison of
928 $got_v with the elements of @elements.
929 "superbagof" is however slightly relaxed, such that $got may contain
931 things not in @elements, but must at least contain all @elements.
932 So:
934 # pass
936 cmp_deeply( [1, 1, 2], superbagof( 1 ) );
937 # fail: not enough 1's in superbag
939 cmp_deeply( [1, 1, 2], superbagof( 1, 1, 1 ));
940 subbagof
942 cmp_deeply( \@got, subbagof(@elements) );
944 This function works much like "bag", and performs a bag comparison of
946 $got_v with the elements of @elements.
947 This is the inverse of "superbagof", and expects all elements in $got
949 to be in @elements, while allowing items to exist in @elements that are
950 not in $got
951 # pass
953 cmp_deeply( [1], subbagof( 1, 1, 2 ) );
954 # fail: too many 1's in subbag
956 cmp_deeply( [1, 1, 1], subbagof( 1, 1, 2 ) );
957 HASH COMPARISONS
959 Typically, if you're doing simple hash comparisons,
960 cmp_deeply( \%got, \%expected )
962 is sufficient. "cmp_deeply" will ensure %got and %hash have identical
964 keys, and each key from either has the same corresponding value.
965 superhashof
967 cmp_deeply( \%got, superhashof(\%hash) );
969 This will check that the hash %$got is a "super-hash" of %hash. That is
971 that all the key and value pairs in %hash appear in %$got but %$got can
972 have extra ones also.
973 For example
975 cmp_deeply({a => 1, b => 2}, superhashof({a => 1}))
977 will pass but
979 cmp_deeply({a => 1, b => 2}, superhashof({a => 1, c => 3}))
981 will fail.
983 subhashof
985 cmp_deeply( \%got, subhashof(\%hash) );
987 This will check that the hash %$got is a "sub-hash" of %hash. That is
989 that all the key and value pairs in %$got also appear in %hash.
990 For example
992 cmp_deeply({a => 1}, subhashof({a => 1, b => 2}))
994 will pass but
996 cmp_deeply({a => 1, c => 3}, subhashof({a => 1, b => 2}))
998 will fail.
1000
1002 deep_diag
1003 my $reason = deep_diag($stack);
1005 $stack is a value returned by cmp_details. Do not call this function
1007 if cmp_details returned a true value for $ok.
1008 "deep_diag()" returns a human readable string describing how the
1010 comparison failed.
1011
1013 You've written a module to handle people and their film interests. Say
1014 you have a function that returns an array of people from a query, each
1015 person is a hash with 2 keys: Name and Age and the array is sorted by
1016 Name. You can do
1017 cmp_deeply(
1019 $result,
1020 [
1021 {Name => 'Anne', Age => 26},
1022 {Name => "Bill", Age => 47}
1023 {Name => 'John', Age => 25},
1024 ]
1025 );
1026 Soon after, your query function changes and all the results now have an
1028 ID field. Now your test is failing again because you left out ID from
1029 each of the hashes. The problem is that the IDs are generated by the
1030 database and you have no way of knowing what each person's ID is. With
1031 Test::Deep you can change your query to
1032 cmp_deeply(
1034 $result,
1035 [
1036 {Name => 'John', Age => 25, ID => ignore()},
1037 {Name => 'Anne', Age => 26, ID => ignore()},
1038 {Name => "Bill", Age => 47, ID => ignore()}
1039 ]
1040 );
1041 But your test still fails. Now, because you're using a database, you no
1043 longer know what order the people will appear in. You could add a sort
1044 into the database query but that could slow down your application.
1045 Instead you can get Test::Deep to ignore the order of the array by
1046 doing a bag comparison instead.
1047 cmp_deeply(
1049 $result,
1050 bag(
1051 {Name => 'John', Age => 25, ID => ignore()},
1052 {Name => 'Anne', Age => 26, ID => ignore()},
1053 {Name => "Bill", Age => 47, ID => ignore()}
1054 )
1055 );
1056 Finally person gets even more complicated and includes a new field
1058 called Movies, this is a list of movies that the person has seen
1059 recently, again these movies could also come back in any order so we
1060 need a bag inside our other bag comparison, giving us something like
1061 cmp_deeply(
1063 $result,
1064 bag(
1065 {Name => 'John', Age => 25, ID => ignore(), Movies => bag(...)},
1066 {Name => 'Anne', Age => 26, ID => ignore(), Movies => bag(...)},
1067 {Name => "Bill", Age => 47, ID => ignore(), Movies => bag(...)}
1068 )
1069 );
1070
1072 Combining "cmp_details" and "deep_diag" makes it possible to use
1073 Test::Deep in your own test classes.
1074 In a Test::Builder subclass, create a test method in the following
1076 form:
1077 sub behaves_ok {
1079 my $self = shift;
1080 my $expected = shift;
1081 my $test_name = shift;
1082 my $got = do_the_important_work_here();
1084 my ($ok, $stack) = cmp_details($got, $expected);
1086 unless ($Test->ok($ok, $test_name)) {
1087 my $diag = deep_diag($stack);
1088 $Test->diag($diag);
1089 }
1090 }
1091 As the subclass defines a test class, not tests themselves, make sure
1093 it uses Test::Deep::NoTest, not "Test::Deep" itself.
1094
1096 Currently any CODE, GLOB or IO refs will be compared using shallow(),
1097 which means only their memory addresses are compared.
1098
1100 There is a bug in set and bag compare to do with competing SCs. It only
1101 occurs when you put certain special comparisons inside bag or set
1102 comparisons you don't need to worry about it. The full details are in
1103 the "bag()" docs. It will be fixed in an upcoming version.
1104
1106 SPECIAL CARE WITH SPECIAL COMPARISONS IN SETS AND BAGS
1107 If you use certain special comparisons within a bag or set comparison
1108 there is a danger that a test will fail when it should have passed. It
1109 can only happen if two or more special comparisons in the bag are
1110 competing to match elements. Consider this comparison
1111 cmp_deeply(['furry', 'furball'], bag(re("^fur"), re("furb")))
1113 There are two things that could happen, hopefully "re("^fur")" is
1115 paired with "furry" and "re("^furb")" is paired with "furb" and
1116 everything is fine but it could happen that "re("^fur")" is paired with
1117 "furball" and then "re("^furb")" cannot find a match and so the test
1118 fails. Examples of other competing comparisons are "bag(1, 2, 2)" vs
1119 "set(1, 2)" and "methods(m1 => "v1", m2 => "v2")" vs "methods(m1 =>
1120 "v1")"
1121 This problem is could be solved by using a slower and more complicated
1123 algorithm for set and bag matching. Something for the future...
1124
1126 A special comparison (SC) is simply an object that inherits from
1127 Test::Deep::Cmp. Whenever $expected_v is an SC then instead of checking
1128 "$got_v eq $expected_v", we pass control over to the SC and let it do
1129 its thing.
1130 Test::Deep exports lots of SC constructors, to make it easy for you to
1132 use them in your test scripts. For example is "re("hello")" is just a
1133 handy way of creating a Test::Deep::Regexp object that will match any
1134 string containing "hello". So
1135 cmp_deeply([ 'a', 'b', 'hello world'], ['a', 'b', re("^hello")]);
1137 will check 'a' eq 'a', 'b' eq 'b' but when it comes to comparing 'hello
1139 world' and "re("^hello")" it will see that $expected_v is an SC and so
1140 will pass control to the Test::Deep::Regexp class by do something like
1141 "$expected_v->descend($got_v)". The "descend()" method should just
1142 return true or false.
1143 This gives you enough to write your own SCs but I haven't documented
1145 how diagnostics works because it's about to get an overhaul
1146 (theoretically).
1147
1149 By default, Test::Deep will export everything in its "v0" tag, as if
1150 you had written:
1151 use Test::Deep ':v0';
1153 Those things are:
1155 all any array array_each arrayelementsonly arraylength arraylengthonly bag
1157 blessed bool cmp_bag cmp_deeply cmp_methods cmp_set code eq_deeply hash
1158 hash_each hashkeys hashkeysonly ignore Isa isa listmethods methods noclass
1159 none noneof num obj_isa re reftype regexpmatches regexponly regexpref
1160 regexprefonly scalarrefonly scalref set shallow str subbagof subhashof
1161 subsetof superbagof superhashof supersetof useclass
1162 A slightly better set of exports is the "v1" set. It's all the same
1164 things, with the exception of "Isa" and "blessed". If you want to
1165 import "everything", you probably want to "use Test::Deep ':V1';".
1166 There's another magic export group: ":preload". If that is specified,
1168 all of the Test::Deep plugins will be loaded immediately instead of
1169 lazily.
1170
1172 Test::More
1173
1175 Ricardo Signes <rjbs@cpan.org>
1176
1178 Fergal Daly <fergal@esatclear.ie>, with thanks to Michael G Schwern for
1179 Test::More's is_deeply function which inspired this.
1180 Please do not bother Fergal Daly with bug reports. Send them to the
1182 maintainer (above) or submit them at the issue tracker
1183 <https://github.com/rjbs/Test-Deep/issues>.
1184
1186 Copyright 2003, 2004 by Fergal Daly <fergal@esatclear.ie>.
1187 This program is free software; you can redistribute it and/or modify it
1189 under the same terms as Perl itself.
1190 See http://www.perl.com/perl/misc/Artistic.html
1192perl v5.36.0 2022-07-22 Test::Deep(3)