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Manual Reference Pages  -  TEST::ASSERTIONS (3)

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Test::Assertions - a simple set of building blocks for both unit and runtime testing



        #ASSERT does nothing
        use Test::Assertions;
        #ASSERT warns "Assertion failure"...
        use Test::Assertions qw(warn);
        #ASSERT dies with "Assertion failure"...
        use Test::Assertions qw(die);
        #ASSERT warns "Assertion failure"... with stack trace
        use Test::Assertions qw(cluck);
        #ASSERT dies with "Assertion failure"... with stack trace
        use Test::Assertions qw(confess);
        #ASSERT prints ok/not ok
        use Test::Assertions qw(test);
        #Will cause an assertion failure
        ASSERT(1 == 0);
        #Optional message
        ASSERT(0 == 1, "daft");
        #Checks if coderef dies
                DIED( sub {die()} )
        #Check if perl compiles OK
        #Deep comparisons
                EQUAL(\@a, \@b),
                "lists of widgets match"        # an optional message
                EQUAL(\%a, \%b)
        #Compare to a canned value
                EQUALS_FILE($foo, bar.dat),
                "value matched stored value"
        #Compare to a canned value (regex match using file contents as regex)
                MATCHES_FILE($foo, bar.regex)
        #Compare file contents
                FILES_EQUAL(foo.dat, bar.dat)
        #returns not ok for Foo::Bar Tests (1 errors in 3 tests)
                 [ok 1, not ok 2, A comment, ok 3], Foo::Bar Tests, 0
        #Collate results from another test script
        #File routines
        $success = WRITE_FILE(bar.dat, hello world);
        ASSERT( WRITE_FILE(bar.dat, hello world), file was written);
        $string = READ_FILE(example.out);
        ASSERT( READ_FILE(example.out), file has content );

The helper routines don’t need to be used inside ASSERT():

        if ( EQUALS_FILE($string, $filename) ) {
                print "File hasnt changed - skipping\n";
        } else {
                my $rc = run_complex_process($string);
                print "File changed - string was reprocessed with result $rc\n";
        ($boolean, $output) = COMPILES(;
        # or...
        my $string;
        ($boolean, $standard_output) = COMPILES(, 1, \$string);
        # $string now contains standard error, separate from $standard_output

In test mode:

        use Test::Assertions qw(test);
        plan tests => 4;
        plan tests;                                     #will attempt to deduce the number
        only (1,2);                                     #Only report ok/not ok for these tests
        ignore 2;                                       #Skip this test

        #In test/ok mode...
        use Test::Assertions qw(test/ok);
        ok(1);                                          #synonym for ASSERT


Test::Assertions provides a convenient set of tools for constructing tests, such as unit tests or run-time assertion checks (like C’s ASSERT macro). Unlike some of the Test:: modules available on CPAN, Test::Assertions is not limited to unit test scripts; for example it can be used to check output is as expected within a benchmarking script. When it is used for unit tests, it generates output in the standard form for CPAN unit testing (under Test::Harness).

The package’s import method is used to control the behaviour of ASSERT: whether it dies, warns, prints ’ok’/’not ok’, or does nothing.

In ’test’ mode the script also exports plan(), only() and ignore() functions. In ’test/ok’ mode an ok() function is also exported for compatibility with Test/Test::Harness. The plan function attempts to count the number of tests if it isn’t told a number (this works fine in simple test scripts but not in loops/subroutines). In either mode, a warning will be emitted if the planned number of tests is not the same as the number of tests actually run, e.g.

        # Looks like you planned 2 tests but actually ran 1.


plan $number_of_tests Specify the number of tests to expect. If $number_of_tests isn’t supplied, ASSERTION tries to deduce the number itself by parsing the calling script and counting the number of calls to ASSERT. It also returns the number of tests, should you wish to make use of that figure at some point. In ’test’ and ’test/ok’ mode a warning will be emitted if the actual number of tests does not match the number planned, similar to Test::More.
only(@test_numbers) Only display the results of these tests
ignore(@test_numbers) Don’t display the results of these tests
ASSERT($bool, $comment) The workhorse function. Behaviour depends on how the module was imported. $comment is optional.
ASSESS(@result_strings) Collate the results from a set of tests. In a scalar context returns a result string starting with ok or not ok; in a list context returns 1=pass or 0=fail, followed by a description.

 ($bool, $desc) = ASSESS(@args)

is equivalent to

 ($bool, $desc) = INTERPRET(scalar ASSESS(@args))

ASSESS_FILE($file, $verbose, $timeout)

 $verbose is an optional boolean
 default timeout is 60 seconds (0=never timeout)

In a scalar context returns a result string; in a list context returns 1=pass or 0=fail, followed by a description. The timeout uses alarm(), but has no effect on platforms which do not implement alarm().

($bool, $desc) = INTERPRET($result_string) Inteprets a result string. $bool indicates 1=pass/0=fail; $desc is an optional description.
$bool = EQUAL($item1, $item2) Deep comparison of 2 data structures (i.e. references to some kind of structure) or scalars.
$bool = EQUALS_FILE($string, $filename) Compares a string with a canned value in a file.
$bool = MATCHES_FILE($string, $regexfilename) Compares a value with a regex that is read from a file. The regex has the ’^’ anchor prepended and the ’$’ anchor appended, after being read in from the file. Handy if you have random numbers or dates in your output.
$bool = FILES_EQUAL($filename1, $filename2) Test if 2 files’ contents are identical
$bool = DIED($coderef) Test if the coderef died
COMPILES($filename, $strict, $scalar_reference) Test if the perl code in $filename compiles OK, like perl -c. If $strict is true, tests with the options -Mstrict -w.

In scalar context it returns 1 if the code compiled, 0 otherwise. In list context it returns the same boolean, followed by the output (that is, standard output and standard error <B>combinedB>) of the syntax check.

If $scalar_reference is supplied and is a scalar reference then the standard output and standard error of the syntax check subprocess will be captured <B>separatelyB>. Standard error will be put into this scalar - IO::CaptureOutput is loaded on demand to do this - and standard output will be returned as described above.

$contents = READ_FILE($filename) Reads the specified file and returns the contents. Returns undef if file cannot be read.
$success = WRITE_FILE($filename, $contents) Writes the given contents to the specified file. Returns undef if file cannot be written.


When Test::Assertions is imported with no arguments, ASSERT is aliased to an empty coderef. If this is still too much runtime overhead for you, you can use a constant to optimise out ASSERT statements at compile time. See the section on runtime testing in Test::Assertions::Manual for a discussion of overheads, some examples and some benchmark results.


The following modules are loaded on demand:



Test and Test::Simple Minimal unit testing modules
Test::More Richer unit testing toolkit compatible with Test and Test::Simple
Carp::Assert Runtime testing toolkit


        - Declare ASSERT() with :assertions attribute in versions of perl >= 5.9
          so it can be optimised away at runtime. It should be possible to declare
          the attribute conditionally in a BEGIN block (with eval) for backwards


Test::Assertions::Manual - A guide to using Test::Assertions


$Revision: 1.54 $ on $Date: 2006/08/07 10:44:42 $ by $Author: simonf $


John Alden with additions from Piers Kent and Simon Flack <cpan _at_ bbc _dot_ co _dot_ uk>


(c) BBC 2005. This program is free software; you can redistribute it and/or modify it under the GNU GPL.

See the file COPYING in this distribution, or

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